You need good gear to make this easier, using a board with high values, especially Tricks, as it will allow you to get to Tricky/Super Tricky faster to bust out Über and Signature moves.
Charge up your jumps to spin/flip faster. Doing basic tricks off the ground and performing manuals will keep your meter running and your combo multiplier going. Avoid rewinding but if you're having a good run it's okay if you're gaining back more than you lose.
Runs that are easier to trick off of have higher gold medal scores, and harder runs have lower scores, so choose whichever you think you'd have a better chance of winning. I recommend Serenity, it's a huge course with tons of grinds and jumps.
If you need a boost, buy the best Trick mod you can. Characters with Tricky+ perks are Mac (+15), Eddie (+15, Gamestop Preorder only), Kaori (+10), Ty (+10), Zoe (+5), and Griff (+5).