Always pop, but not too agressively or you'll throw yourself off balance.
Start off with straight airing or doing some simple grabs (safety, japan etc) and work your way up. Practice switch skiing and sliding obstacles unnatural (both ways).
Try 180s and 270s off on small stuff. When rotating, use head and shoulders (like the shampoo hurrdurr).
And most importantly, don't just sit around watching trick tips, get out there and try it and ask other skiers if your struggling, you'll make new friends and get advice from someone who can actually see you skiing and tell what your doing wrong.
And falling is just a part of progressing, the best way to get over fear is to fall.