1. Abuse your first day.

The first day is the tutorial day with Farm Fam, while her tutorial is going, time is essentually frozen at noon, you can make huge use of this to get a jump start on your farm, cleaning up and organzing without worrying about suddenly passing out from time. This rolls right into the next tip.

2. Loot for starting cash

Most worlds spawn between 2-3 abandoned cabins and one abandoned mine. take your hammer and lay waste to them for a huge boost to starting cash, take everything. You might not think a broken window is worth alot of money, but it is. Its best to do this on your first day so you can take your time and not feel pressured. you can also use the light wooden planks from the cabins/mine to build your barn which will soon see use.
Version 1.0 change: They added a slider that lets you add up to 4 total starter farms to the world, obviously with MP intents. I recommend even when playing solo to spawn all 4, its a nice boost to starting revenue and building resources to lay waste to the other 3 farms.

3. Unless you love animals, stash your pet

The pet you are given does eventually reward you with golden seeds once its happy enough, but its a takes money to make money kind of thing, pet food is rather expensive for the first season or so since you have alot you need to buy. Its best to either store your pet house till you get further along, so then its not starving/bad health.

4. Go bug farming with some specifics in mind

Bug farming can be a good activity once your daily chores are done to make money, be sure to keep two rhino beetles (found on trees) and any queen bees you find. You might be tempted to sell the queen bees for money since they are worth a decent amount, but don't.

1. What crops are best?

This is my opinion but:
Spring: Cabbage, turn them into cabbage soup for a boost
Summer: Strawberries, your first season sell them, after that save them for winter.
Fall: Sugar Cane and Sugar Beats, save for winter
Winter: Sugar Beats, take all you made in Fall and winter and turn into sugar. if you have any strawberries make strawberry jam with the sugar for a massive boost to profit.

2. Bee Empire

Remember how I said keep your queens? Any time you can afford it, buy an apiary and load a queen into it, it will take 13 days to get your first honey from an apiary but after that its decent money every 3 days. another thing that makes sense for you to do is try to get all your apiaries to pop the same day, which is easily done by not gathering honey till they are all ready to be gathered, it will line all their timers up. What makes them good right now is they are consistant money all seasons and they have no hunger costs.

3. Cook! For Riah's sake! Cook!

Cooking massively boosts value to most crops, while boring to do the money should not be ignored. Some more than others, I found the Jams and soups are the biggest boost for the smallest effort.

4. Livestock, Don't have a cow.

You'll be given two cows and one chicken starting out.... and that will do at the start. Livestock are like Apiaries but way more expensive, they are consistant money but the amount isn't too great, and unlike apiraries they have a hunger cost. So either just keep the ones you start with... or even sell them for a huge boost to your starting money in other areas. I am not saying livestock can't be profitable, but its in my opinion a slower start up so you may want to focus elsewhere at first.

5. You can get WHAT on the internet?

Once you have some loose money two things I recommend getting are the Catalogue and Shipping bin, these will cost a combined 5000 petals, but they are worth it cause you can easily see how much of something you are getting, not restricted to that store's current rotation of stock, and its not as far of a walk to get stuff, which depending on if you move home this could be very important to you.
Version 1.0 change: they now make you have to go through a quest with Lief to get to be able to acquire these, its still worth doing as soon as you possibly can.

Heres some simple tricks with the mechanics not everyone might know.

If you cast your line fishing and pull up the esc menu, the timer freezes. However you can still hook fish, you'll need to unpause to do the reeling in minigame, but this allows you to catch more fish in a day (doesn't work in multiplayer. DUH) Patched as of 1.1.45

When cooking, if you use your scroll wheel to change tool, you will skip the cooking animation, this is useful for frying and boiling where the animation is long so you can keep a steady flow when cooking a mass amount of food.

Always try to milk your cows twice, its not very often but occasionally they can be milked twice a day, not sure if its a bug or what, but don't let it go to waste.

When harvesting crops, pull out your bug net, you'll get an extention to your harvesting range. You wont have to run around so much.

To get jars of water without buying them, simply take empty jars to the sink in your house and interact. The game does not tell you this so its easy to miss.