The options/controls menu mis-names the keys and can cause confusion so here's some basic keys for basic actions.

-You should know WASD
-Enter changes the view so you can get third person etc
-Space is handbrake
-Esc is pause

As for the clutch control I assume that's LMB/RMB/MMB but I don't drive clutch so I have no idea (If someone does please explain in the comments)

Everything else IS clearly explained in the pause menu

First off I'm a keyboard and mouse driver so this advice may only apply to other keyboard users due to the present handicap. Secondly at time of writing I admit I have only used the AE86 and not the other cars (sue me) so if this doesn't work with other cars, then I can't help ya.

As far as I've figured out there's 4 different ways to achieve a drift:

1. Turn while driving at a fast speed
2. Let off the gas for a split second or two while turning
3. Apply the handbrake while initiating the turn
4. Apply the brakes while initiating the turn

These are ordered from least sharp to most sharp, with braking almost putting your car into a spinout or 180 depending on tuning and application, even if only tapped.

I use 1. when there's a slight curve in the road, 2. when I have a 90 degree turn or less, and 3. or 4. for very sharp turns. There is not a huge difference between 3. and 4. but I find using the handbrake rather than the brakes seems to give the car more stability and "slide" to its drift rather then getting halfway through the drift and losing momentum in turn coming to a halt.

Final point is don't blow off the "turbo" in the tuning menu. Sure your car may accelerate at unrealistic speeds, but because of the raw power it makes the rear swing out easier, meaning you can drift at faster speeds much more easily. I find optimal settings seem to be between .50 and 1 for the boost ratio. Any less and you don't really feel a difference and any more and the car is hard to control on straights and especially light corners.

Thanks for reading and I hope I was able to help some people out, I'm still trying to get the full hang of it myself. If anyone has any tips or advice they think might help other people out just drop it in the comments and I might add it to the guide. Thanks!