Here is a list of all the skills you can perform in the game:
Air _______ All four wheels are off the ground
Burnout _______ Accelerate to the point of losing traction and causing tire smoke, on pavement
Drafting _______ Follow closely behind a car you are racing against while doing at least 50mph.
Drift _______ Slide sideways for at least 10 meters without using the E-brake.
E-Drift _______ Use the E-brake to slide sideways for at least 10 meters.
Infection _______ Multiplayer game mode Infection - infect another player
J-Turn _______ Reverse, turn 180, accelerate forward
Left For Dead _______ in Infected, be the last survivor (for a period of time?)
Near Miss _______ Pass another car you are not racing against at at least 50mph
One Eighty _______ Use the e-brake to spin your car around and drive away in the opposite direction.
Pass _______ Pass a car you are racing against.
Royal Pardon _______ Lose King status? (to the player you took it from?)
Sketchy Pass _______ Pass with damage?
Speed _______ Travel 450 meters while doing more than 100mph the entire way.
Trading Paint _______ Scrape a car as you Pass (possibly in opposite directions)
Two Wheels _______ Drive on two wheels (different axles? with or without flipping?)
Wreckage _______ Hit something breakable, like small signs and fences - not trees
Taken from http://www.forums.forzamotorsport.net/turn10_postst214_Skill...Chain these together to earn over 3000 points, each different skill will add to the multiplier which goes in decimal places up from 1, 1.1, 1.2, 1.3 etc to make your score larger. So vary your skills and this is easy.