This is the information I wish I knew the first days of finding this gem of a game. I hope it helps you become more effective faster. This is not a tactical guide, but includes more information on the basics, and how to create an autoexec.cfg for custom bindings. There are many excellent tactical and game mode guides up already.

Insurgency attempts to put the emphasis on tactically positioning your team effectively. This is why it feels so different than many other FPS. Visibility gets bad, enemies seem to pop up out of nowhere, etc. Having teammates positioned and aimed in the right direction to support and be supported will be rewarded!

Play the objective! Please.
It serves no one on the server to try run-gun stuff. Most the bad guys are near the objectives. More bad guys, more potential kills and cap points. And you get WAY more points for objectives!

The game is ABOUT capping. So cap. Caps cap faster with more meat on them. Be the meat on them. One cap point is worth 10 kills.

Best way to start playing Insurgency?
IMO, play Coops a lot! You learn the maps, improve your aim, figure out loadouts and cleanup your tactical awareness and bad habits from other shooters.

Big Scope?
You're doing it wrong. IMO, 2x scope is the most magnification you really need, unless you're the teams main anti-sniper. Even after the July 2015 changes, 4x and 7x scopes are for overwatch roles. Most of the big scopes limit peripheral vision, zoom slowly, and have tiny view apertures. Meaning, unless you are well practiced, you'll get killed more often. 90% of combat in the game occurs well inside 100 meters. When you're starting out, stick to 1x scopes or ironsights.

Some weapons have great ironsights (AKs, MP5, etc.) and some have poorer sights like M16 and M4 (they obsure more than AK sights.) It's good to be practiced with ironsights.

Night vision
B key is default.

Flashlight
Flashlight is awesome (G key). Just turn it off when you can. DO NOT aim it at friendlies or they will not be.

Laser
The laser (G key) is the only way to reliably use hip fire. The game has a dead(ish) zone near the center of your view and hip fire will NOT be in the center of your screen. The laser literally just marks your aim point. It has no other effect on weapon handling.

Since the October AI improvements, AI are now attracted to Lasers. This is a two edged sword. They will find you easier, but they may also line up to be killed. SAW bait!

Best Guns to start with? (IMO)
Pretty much any AR or carbine. Start with these. Typically 2 shots from anything will kill so weapon choice is a personal matter but ARs are a great place to start.
AKM, AK74u, M16/M4/mk18 Fighter, Militant, Rifleman, Specialist
AP ammo. Heavy Barrel, iron sights, Armor, No pistol.

Specialty Grenades
October 2015, the Smoke grenades now function vs AI. Prior to the update, all smoke did on coop was blind your team. Now smoke is especially useful when you are undermanned and pinned down. Pop a smoke while defending a cap.

Against bots, put a smoke on your position. Against humans, you generally throw them where you are going.

Incendiaries and Molly's can be used to deny an area or passage. Stairs and hallways and corners. The biggest downside is they are very hard to see through and may block yourself in.

Frags, incendiary and Flashes can "cook." Detonation time is 5 seconds from left-mouse button click, if you throw it or not! Molly's don't "cook." Don't over-estimate how far you can throw. They are not going as far as you think. Middle-mouse will underhand or roll a grenade. Grenades always reticule the center of the screen, unlike hipfire.

Left-mouse starts the 5 second timer immeadiately and cooks the 'nade. Right-mouse will pull the pin but not throw the spoon. Once you release the right-mouse and throw, the spoon is flipped, and the 'nade timer starts for the full 5 seconds.

On default servers, there are two explosive equipment slots. The second slot will carry two grenades using the Heavy Chest Carriers. This slot will also be replaced by pickups if you are holding a gun when you pick up a munition. An empty slot will be filled before dropping anything. If you equip a munition, that item will be replaced by the next pick-up.

FlashBangs
Only use Flashbangs when you are the point soldier of a frontal assault element. Keep this in mind and you will be an asset to your team. Throwing 'Bangs from the rear will just blind your team and get you kicked or killed.

Economy
On more strict servers, you will have only a few points to invest in your equipment. Generally, it is best to invest in your primary weapon the most. Skip a pistol, take the 1 point Chest carrier, no grenades. Be sure to pick up ordinance as you find it (after the enemies are clear in an area! Countless times I have seen guys wiped looking for the right 'nade on the ground!)

Armor is very important. You may have to wait to get heavy armor. Heavy armor also slows down your movement. Light armor is free for Security and 1 point for Insurgents. In Survival mode, take a stock pistol, light armor, and a chest rig when you can afford it. Without a rig or carrier you have very limited ammo.

Each round you are defeated, your supply increases by 1 point as a handicap system. Add goodies as you go.

As mentioned, a solid low-supply base setup would be:
AP ammo. Heavy Barrel, iron sights, Armor, Rig or Carrier, No pistol. No grenades.

Ironsight sensitivity (ADS, aim down sights)
This is for ironsights and pistols only. Try .6 and work from there (+/- .02 increments.)

Scope Sensitivity
This is for all scopes including 1x scopes. Try 2.5 and work from there. (+/- .02 increments.)

Mouse DPI
Turn off mouse acceleration.
Turn on RAW mouse input.

With a ruler, measure how far you move your mouse to turn your soldier 360o.
10" (25 cm) is a good place to start. It may feel weird and slow at first, but trust me. This single tip will likely double your k/d ratio. Long distance maps (scope 1.90000) may require different scope zoom values than shortrange (2.70000). With a 4x or 7x scope you may need to go as low as .9 to make it more usable at extreme distances.

Driver and system DPI is meaningless. The only setting that really matters is mouse travel to turn 360o. Everyone has different mice, drivers and such, so the numbers mean nothing to another player. Try starting with 10" (25 cm) to turn 360o..

Graphic issues
Sometimes the game bugs out and you seem like you're walking in the air, or your sights are way off, or the screen jitters when you scope. Quit the game, and relaunch from Steam should fix it. Or use the 'restart video' bind in the autoexec.cfg I posted below. You can also force a video reset in-game by changing resolution and back in settings.

Mute obnoxious players. A very useful tip!
in game hit TAB. Click the tiny Speaker Icon at the far right of the column. Player silenced, more fun, less trolls and mic spam. Chatty players can also obscure important audio information (foot steps!)

Tip: Don't be an obnoxious player. You'll just get silenced and won't make friends. And you probably will not even know you've been silenced.

Is your mic is too loud and distorted? Too quiet and inaudible?
This is common. If you're too loud you just sound like bad static, and you'll get silenced. Reduce/increase Steam mic output in Settings by 10% and try again. Ask in-game how you sound. In game sound is louder than the Steam test so ask.

Health
On normal and Pure servers, Health NEVER resets. You start with 100 HP at spawn. When this dwindles to 0, you die. Resupply does not reset health to 100. Some servers may reset health at the start of a new round, but generally, you have 100 hp per spawn. Be careful!

Suppression
Players can become suppressed when they are damaged or are taking fire around their position. But being suppressed does not mean you are being damaged. Taking damage will also suppress you. You can't tell, but you can guess. If you are suppressed quickly, you can assume you were damaged. If suppression is building over time, you may or may not have been damaged.

AI also suffer suppression, which reduces their accuracy, ability to see, and/or ability to attack.

Never cross in front of a teammate who is sighted up!
If you walk in front of a teammate who is aiming, you are both about to be killed. You block your teammates angle, and they are likely aiming because there is an enemy where he is aiming. They can't shoot through you to kill the enemy that pops up. Nor will you see him in time. Solution? Always cross behind teammates! Use comms and announce crossing.

Don't merge soldiers.
Soldier do block each other, but at times team soldier models can overlap. Since bullets are emitted near a models eyes bullets will hit the soldier sharing the same space! It happens very often and is a common source of friendly fire, including both at once. Don't side-step in to them. Keep aware of your surroundings. Situational Awareness is critical.

Down in Front!
When in front of your group, crouch, so your team can shoot over your head. Stand up carefully! Stay near walls so your teammates have a clear firing lane in the center of an area. If you are on the left side, look and cover to the right. When on a right hand wall, look and cover to the left.

In coop, don't move so much!
An AI will either hit you or miss you. Unlike in PvP, where jiggle strafing can confuse a human, against AI you just compromise your aim and block other teammates view of the area in front getting you and increase the chances you will get TK'd and/or get your teammate killed since you both are in the way of your squads fire.

Avoid the center of hallways and passages unless you are bringing up the rear. One guy in front can halve your teams firepower by blocking up to 4 guns behind you.

Too Many Snipers
I have seen games where my team outnumbers the enemy, but all 4 guys have 4-7x scopes and are 200 meters from the cap on an urban map. Thats 4 useless teammates who can't get to the cap point in time or bother to try... I define a "Sniper" as any player with a rifle and a high-magnification scope.

Insurgency doesn't allow (or its just a bit flaky) custom binds in the cfg file or from console. This is by design as a pure-competitive server may disallow autoexec.cfg files.

To make your own autoexec.cfg file:
1) Make a new empty .txt file in the same directory as the config.cfg file. Name it autoexec.cfg.
For example: C:\Program Files (x86)\Steam\steamapps\common\insurgency2\config

In Notepad, paste the snippet below into your autoexec.cfg file and save. (This is a partial of my own custom file. Change as it suits you.)

////////////////////////////////////////////////////////////////////////////
clear
joystick 0 //disables joystick and controller input

bind "o" "ins_bot_difficulty" //displays bot level in console

bind "h" "say !bt" //bullet-time mod binding
bind "6" "say !props" //Invoke Armory mod menu
bind "9" "slot9" //sometimes a default bind will corrupt. "9" will exit Prop Menu

bind "j" inventory_resupply //one key resupply
bind "\" snd_restart // resets snd. This is very useful.
bind "/" "hud_reloadscheme; snd_restart; record fix; stop" //this resets video and sound
bind "7" "cl_showfps 1" // 0
bind "8" "cl_showfps 0" // 9

//Team chat Comms bindings
bind "KP_DEL" "say_team This cap may hot spawn" //keypad .
bind "KP_INS" "say_team Sorry, my bad!" //keypad 0
bind "KP_END" "say_team Don't move up too soon!" //keypad 1
bind "KP_DOWNARROW" "say_team fall back for their rush..." //keypad 2
bind "KP_PGDN" "say_team I think it's time to move up..." //keypad 3

bind "KP_LEFTARROW" "say_team Our Left Flank crumbled!" //keypad 4
bind "KP_5" "say_team Enemy on our position!!" //keypad 5
bind "KP_RIGHTARROW" "say_team Our Right Flank has fallen!" //keypad 6

bind "KP_HOME" "say_team Watch your back!" //keypad 7
bind "KP_UPARROW" "say_team Get on cap!" //keypad 8
bind "KP_PGUP" "say_team I'm down..." //keypad 9


host_writeconfig

////////////////////////////////////////////////////////////////////////////

Right Click>Get properties on Insurgency
Launch Options button
-autoexec.cfg

I hope this little guide helps someone out. I appreciate the feedback and ratings and will keep adding things as I think of them. I want to keep it basic.

Be careful out there!