Tiny Baetis mayflies are perhaps the most commonly encountered and imitated by anglers on all American trout streams due to their great abundance, widespread distribution, and trout-friendly emergence habits.
With those bigger flies I find it easier to cast if you slow everything down. When I first started out it seemed to take a year before the loop would open and the rod load. If you try to cast too fast you will lose all momentum and end up with a mess at your feet. Over-lining helps keep that energy through the cast, and the cast tends not to collapse as much.