The key to trickit is to get big air and do big moves. Spins are worth less than flips. What you ideally want to do is always aim for the misty (which is where you spin and flip in the same move. Achieved by using the diagonals when winding up or in the air)
Flips and spins alone are not worth much so obviously you add board grabs to them. Single input grabs such as just square or circle etc, are worth less than the 2 input grabs such as square-circle or square-triangle. And as long as you have the air you always want to tweak the grab using R2, this makes the move take longer to end so make sure you have enough time to finish it before landing so you don't wipe out.
Next is your multiplier. Each time you complete a trick your multiplier will go up by 1. You want to max this out as soon as possible so that all your tricks come in at x20. Fastest way to do this is to hit tricky, then hit a grind and spam the grind moves, you don't even have to hold them just alternate between them fast as you can to get up to x20.
You only repeat a trick if you do the same trick in a row twice.This is seriously detrimental to building you score so don't do it. (for e.g your signature move could land you 20,000 points, if you do it again straight away you will get 2,000!) So you can alternate between just 2 tricks that your comfortable with as long as you don't do the same one twice. Your biggest scoring move is your super uber signature move (L2 + R2 and any other button) you should get comfortable using this every other trick for the biggest points!
Keeping Tricky active from your first or second jump on a run is also very important. Once Tricky is activated you get your super uber moves which score more points, also allowing you to boost infinitely for bigger jumps and faster spins.
You should try to keep your combo throughout the entire run as well. My highest combo was well over 220. Each time you do a trick it adds to the combo points as well as your overall score. When you cash in the combo it multiplies it by the multiplier below your score. Cashing in multiple times is not beneficial as the higher the score from your combo the higher it will cash in when it multiplies by 20. (for e.g. if you build a combo worth 100,000 points and cash in at x20 you will score 2,000,000. If you build the combo score up to 2,000,000 and cash in at x20 you will get 40,000,000 added to your score!)
Hopes these tips help everyone. If you have any other questions I'll try my best to answer them!