Careful
Although it is tempting to go all out and throw caution to the wind, staying patient and careful is the way to completing tricks successfully. In the "Nail the Trick" and "Nail the Grab" modes, the slow-motion camera actually distorts your view so that it is hard to know when to land. Know when to get out of the mode and claim your points, you don't have to push it until you land face first against the concrete. Research your landmark before entering the mode, and once you feel you have passed it, quit the slow-motion camera view.
Similarly, when you have to take out gang skaters on the streets, do not rush in at maximum speed. It actually makes little difference whether you smash them full on or bump them at a slow speed. When there are lots of enemies, it is more effective to ride up to them one at a time slowly and knock them off.
Practice
Do not rush through the various techniques and moves once you have done them a few times. Learn every trick meticulously until it is second-nature. Although in the early stages of the game you can rush through challenges and levels, your lack of experience and intuitive skills will frustrate you at the harder stages later on. Take every level slowly and go out of your way to find challenges and detours even when you have completed the mission itself. Practicing the basics on curbs and rails can earn you upgrades while putting you in good stead for tougher tricks. Practice your Aggro Kicks until you can perform them instinctively by keeping one finger on the trigger control at all times; do not switch between the trigger and other buttons with the same finger.
Scoring
To gain maximum points, perform multiple tricks one after the other. You need to have learned a good number of different moves to do this, but once you can instantly perform each one then simply repeat them consecutively following lift off. Landing on different grind rails and ramps will also continue your points tally, so look for good jump-off areas.