360
Press Down/Right after getting a lot of air.
Realistic back flipSince the back flip trick goes very fast and looks unrealistic, there is another and much better looking way to do one. Use the "Bigger air" trick. After you launch off the ramp, hold Back and you will do a better looking and more realistic back flip. You can also do a front flip like this, but it requires some skill, and big air.
Bigger airTo get bigger air, hold L as you go up the ramp. Release L (ideally when the gauge is full) at the lip of the ramp.
Get a new girlfriendTo get a new girlfriend, win three races in championship mode.