>>1994052
The most important technique: the side attack. When you use it, you instantly regain your grip. This means that if you fuck up and start drifting, you don't lose as much speed. Also, never use the sharp turn (holding Z or R) -- side attack as you turn instead. Again, you lose less speed than sharp turning, you can make tighter turns at higher speeds, and if you happen to hit someone, you'll often kill them. Side attacking is the one thing that let me graduate from Expert to Master. Of course, you'll have to git gud and get familiar with the stages before this will help you very much.
Secondly, I'd stick with Falcon for at least a while. His machine is very well balanced.
Thirdly, whenever you hit a pink strip, which recharge your health, boost on it. Boost comes from health, but for some reason, boosting on pink does NOT cancel out the health gain, so it's basically a free boost.