Learning the tracks is the number 1 thing.

Racebox is the best for this,start with time trials and try to hit every speed pad.

If you think of each track as a sheet of music,each speed class as a different tempo.
The music stays the same,but the tempo gets faster.
It's like learning a guitar riff,air brakes are similar to string bends,side shifts are like hammer on's, barrel rolls are like using the tremolo arm.
When you get fluent at the track/music, then you can put your own interpretation to it.