How do I make my scooter do a 360 like I can make the motorcycles in GTA do?

Its a fairly simple setup... 2 hand brakes and one handle to gas it.

I wouldnt try anything that I do in GTA. lol

1) hold the front brake

2) lean the bike to one side

3) gas full throttle

4) walk it in a circle

5) you dont have to keep it wide open

pick it up...
...turn around...
Just kiddin', if you're talkin' about a "burn out" or "red line", you're probably going to need more horsepower and torque than most scooters can produce. Often times trick riders do a dangerous handbrake maneuver (again dangerous). It's one of those "DON'T TRY THIS AT HOME" things. Find open space and wear protective gear.

A little oil or grease on the tires that are located on the outside of the circle will help. then, using the brake that controls the front, clamp that down, and give it full throttle. Make sure that the wheels are turned in the direction that you want to spin