when a rider starts out trying a trick, i usually film it for a more artsy and creative angle (in other words, a more difficult shot). this way, even if they don't land it, i have the beginning of the trick captured. as they get closer to landing it, i move to a better angle where you can see the landing. then just put the shots together to make it look like one fluid trick.
or you just have the riders do the trick twice, or at least hike for an in-run shot after they land it. they hate that kind of thing, but pressuring your riders to do it is part of being a filmer.