I would suggest starting with the tutorial (even though it is crap) then start with forest frontiers and make your way down the list.

The controls are pretty simple, left click to place, right click to delete(ONLY WHILE IN A CONSTRUCTION MODE). The top of the screen has a bar with different icons, clicking on them will open a menu, each menu allow you to do and see different things, I would suggest messing around and getting used to all of them.
Moving in screen is done by moving your cursor to the edge of the screen, using the arrow keys or holding right click and moving the mouse.

Missions fall into 1 of 3 categories: Build a park from scratch, Expand on a park with a single ride or Turn a pre-existing park into a better one.

This section is mainly for the first 2 categories but can be useful to keep in mind.
Start out by building a cheap gentle ride and a cheap thrill ride (e.g. Merry-go-round and Scrambled eggs). Then raise the park entrance fee to $5 and make the price of the rides to around $1 or so depending on the excitement. Next go into your research tab. I would suggest putting funding on maximum and checking only shops and stall until you get 1 drink stall, 1 food stall, and the Info Kiosk, after that it is up to you how you choose what research does.
Place a washroom near the exit of the thrill ride. Put an info kiosk, a food vendor and a drink vendor near the front of your park, before the pathways branch off. Hire a couple Handymen and a mechanic and security guard(I will talk about these in the staff section of this guide.)

When you start getting guests in your park and you are earning money consider placing a roller coaster, doesn't have to have high intensity or excitement, but a low nausea rating is preferred.(Will talk about this more in the roller coaster section of this guide.)

This section goes in detail of ways to use each staff and how much a single staff member can handle.

Handyman - Your standard janitor, cleans up the park and has a cheap salary.
Uses- I would suggest having a handyman's tab open at all times so you can place him if you notice any messes. No patrol for this handyman.
Most handymen should be put on patrol. A single handyman can reliably cover 7-9 patrol squares (a patrol square is the 4x4 blue grid that appears when clicking while the blue feet button is pushed in on a single staff member's tab). Make sure to have at least 1 handyman patrolling each section of your park. ALMOST NEVER LET YOUR HANDYMEN MOW THE GRASS IT WILL TAKE UP ALL THEIR TIME AND IT DOESN'T AFFECT ENOUGH TO BE WORTH IT.

Mechanics - They fix and check up on rides, $55 salary though so make sure not to place too much.
Uses- Each mechanic can handle 2-4 rides depending on how far apart said rides are. Make sure to put the rides' exit within a mechanics patrol so they can fix and check up on rides. If any mechanic has a rides' exit in their patrol area you can set that ride to being checked up on every 10 minutes. Make sure to have at least 1 mechanic with no patrol (in case of more than 1 ride in a mechanic's patrol braking down at the same time) DO NOT PICK UP A MECHANIC WHO IS HEADING FOR A RIDE TO FIX IT, THIS WILL INTERRUPT THEIR ACTION AND HAVE A DIFFERENT MECHANIC BEING CALLED IN TO FIX THE RIDE!

Security Guards - Their use is to stop the destruction of scenary placed on the path (e.g. Trash Bins and Benches)
Uses- Security guards do not need a patrol, but 1 security guard can reliably cover 8-12 patrol squares. Make sure you have enough but not too much. I normally end up having between 3-5 and I almost never see broken stuff.

Entertainer - They will entertain and cheer up people who see them. Increasing guests' happiness.
Uses- Make them patrol crowded areas like the park entrance or long ride queues.
Side note- The outfit an entertainer wears does not appear to change its affect.

These rides tend to be great at starting off your park and are easy and generally cheap to make.

Gentle Rides - These tend to pay themselves off slower if at all, the worst offenders of this are Haunted House, Car Ride and Ferris Wheel.
The best gentle rides are probably Merry-go-round and Bumper Cars.
Generally speaking start off with a price between $0.50 and $1.00 and go from there. Look at guests thoughts to see if you are charging too much.
Side note- In research gentle rides include transport rides

Thrill Rides - These tend to be rather exciting with a higher intensity and nausea, they can easily pay themselves off.
One of the best thrill rides is Go Karts.
Generally speaking start off with a price between $1.00 and $1.50, but you can start Go Karts at $2.00-$2.50. Look at guests thoughts to see if you are charging too much.
Side note- In research all water rides are categorized as thrill rides.

Water Rides - In my experience these are the worst type of ride, they have high excitement but the main problem is the move so slowly and guests with complain about it taking too long.
The best water ride is easily Boat Hire. Either tracked or un-tracked.
Generally speaking start off with a price between $1.50 and $3.00. Look at guests thoughts to see if you are charging too much.

Transport Rides - These range from slow moving to fast moving, used to either tour the park or make a faster way for guests to navigate the park.
The best ride is probably the standard monorail as it moves the fastest from what I've seen.
Generally speaking start off with a price at $1.00. Look at guests thoughts to see if you are charging too much.
The Shuttle Mode will make a train go between 2 stations (goes to the other station and then back).

Over time due to having more rides in the park or raising the park entrance fee, guests won't pay as much for rides. One fix if the price is going too low is the demolish the ride and re-build it in the same location as the guests will treat it as the new hotness.

Roller Coasters tend to be what draws in the most guests, gives you the highest profit and are almost required in order to beat most maps.
You probably will not start out good at building roller coasters, but practicing to see what works and what doesn't, looking at pre-built roller coasters and watching others build roller coasters is what helped me become a much better roller coast designer in these games.

No matter what roller coaster you can start off charging $2.00 for it and if it is a really good roller coaster maybe even $3.00 approaching $4.00. On-ride photos can be priced anywhere between $1.30 to $2.00.

Each roller coaster has their own unique querks and gimmicks so each person has a favourite set of roller coasters to build. For me its Steel roller coasters (all variations).

Read up the description of each roller coaster before jumping in and trying to build it.

Each ride in your park has an excitement rating, this determines how much people will want to ride the ride and how much money they are willing to pay to ride said ride.

Every ride has an inherent excitement value, this is determined by how fun it is to ride on the ride.

You can increase and rides excitement in 2 major ways.

1) Placing scenary where it is visible from the ride or queue, this is also slightly lengthen the time guests will wait to ride rides. Each scenary item gives not too big of a push but place a lot of scenary and you will see a big change.

2)Making rides visible from other rides/intertwining 2 or more rides. Doing this will increase the excitement on both rides depending on how exciting the other ride is. For example if you have a Roller Coaster intersect with a Car Ride the Car Ride will gain more excitement than the Roller Coaster will, but they both get a benefit. This is the easiest way to overcome those maps requiring you to build plenty high excitement Roller Coasters.

Scenary will increase excitement ratings on all rides it is placed near.

On path scenary - Only useful ones are benches and trash bins.
Trash bins so the guests wont litter and will lessen your handymen's jobs.
Benches are used so guests can have a place to sit while eating, increasing their happiness, but also while a guest is sitting on a bench they will lower there nausea stat and raise their energy stat.

Make sure to put food and drink vendors near crowded portions of the park.
Only put in a few of each Souvenir type shop/stall normally one near the front of your park and one near the back.

Washrooms- Washrooms and places guests will go vomit instead of the ground, I would suggest putting at least 1 near each exit of a ride with a nausea rating higher than 0.75. Along with one near every drink vendor.

I suggest using the standard pricing for each shop/stall.
You can charge 10 or 20 cents for your washrooms so you aren't losing as much money for each washroom you have due to operating costs.

In this section I will give you a step by step walkthrough on how to check up on pre-existing parks.

1) Make sure you have enough staff. You can hire, position and set patrols of staff while game is paused.

2) Check the pricing of the park entrance and rides, edit if you think anything is over/under priced.

3) Check the shops and stalls, most missions that start with a pre-existing park don't have adequate food, drink and washrooms.

4) Add in any gentle/thrill rides you have access to/want to that aren't already in the park. Most thrill/gentle rides serve no purpose being repeated, the exceptions are ones that have different modes, e.g. Gravitron, Motion Simulator.

5) Look at guest's thoughts to determine the main issues (if any) the park has.

On each map you start of with money and loans. You can see how much you have in loans in the finance and loans tab.

How your money is calculated = Cash in account - Loans.

It is always a good idea to pay off loans as quickly as possible as having loans make you pay interest every week in small amounts, but if you ever need just a bit more money to pay for rides you can take more loans. You can take more loans the higher your park value is and the absolute limit is determined by mission.

Paying off your loans is a potential mission goal, I can't remember if they have it in this game, but in RTC2 several missions have the win condition of paying off your loans.

Company Value - Company value is your score for most maps and how you can have your name in the top position of the leader board for any mission. Your company value is your cash in account minus your loans plus your park value. And the park value is how much your park is worth or how much money people would buy the park for.

You might have gotten some awards in your park and are wondering what they do. Each year you randomly get awards if you meet the qualifications of that year (each year is harder to get than the last year and there is SOME randomness in it). You can see all the awards you got in the current year in the awards tab of your park entrance tab.

Each time you gain an award your park value goes up.

Awards I have seen:
Best Value Park Award
Tidiest Park Award
Safest Park Award
Best Park Staff Award
Park With Best Washroom Facilities Award
Park With Best Food Award

If you ever see anything in red text is the message board you will lose park value

Examples of this I have seen:
Guests complaining your entrance fee is too high
Guests complaining about the disgusting state of your park
{insert guest} is lost and can't find exit
{insert ride} has been broken down for too long
{insert accident involving death}
Guests are hungry and can't find any place to buy food
Guests are thirsty and can't find any place to buy drinks
Guests are complaining about how crowded it is in your park

if you see anything in red text your park rating and value will take a big hit.

There are several upsides to running a park with no entrance fee, It is easier to find out a nice pricing on rides, guests will stay in park longer and be happier while in park, and will have more money to spend on rides.

If you have no entrance fee you can do stuff you couldn't do normally, like make sure all vendor items are sold at $1 profit each and having the price of rides be its excitement rating rounded down. e.g. a ride with an excitement value of 1.35 should have a price of $1.30 or a ride with 9.99 excitement should have a price of $9.90.
I only found a couple exceptions to this rule being Merry-go-rounds and Haunted Houses both having way lower caps than their excitement.

There is also some downsides, like not getting the easiest and most reliable source of huge amounts of money (most maps I get around $50k in total from park entrance within the first 3 years), it is a bit harder and difficult to get used to and it is really hard to get a park to start to make money.

It is up to the player on how they wish to play the game.

These types of maps are fairly rare, the 2 that come to mind are Evergreen Gardens and Trinity Islands. These types of maps are ones where you start off with a lot of paths that circle back and make a maze for your guests to navigate without being lost. Most of the time you don't even start off with an Info Kiosk researched.

The Fix = Remove path ways and limit your guests to only being able to navigate a portion of the park. Enter any construction mode and right-click and not-needed paths. Then start off small and slowly extend as you see fit.
Another solution is quickly putting in a transport ride in that stops off at all major parts of the park, the issue is they move kinda slowly (monorail being the fastest, guests complain if it takes too long.)

When I was first playing this game these maps were the hardest and gave me the most trouble.

I will add more to this guide, just comment any questions about the game or if you need more specific help with certain missions and I will gladly help to the best of my ability.

DISCLAIMER I have not beat EVERY map in RTC1 or RTC2 in fact I don't think I have ever even beaten enough maps to see every possible map, but I have played on and beaten a wide variety of this game, or at least enough to have figured out most of this stuff in gameplay and the rest I heard from my friends' experiences with the game and watching other people play the game.