The up B out of shield ALWAYS out-prioritizes Falco's shine after he D-Airs your shield. Do this whenever the Falco tries to pillar you. It works like a charm. Same goes for Fox.
Here are some tips...
-You shouldn't worry about learning to Super Wave Dash. It's much more important to focus on the other basics aspects of Samus's game.
-Don't worry about SHFFLing. Samus isn't the kind of character you spam arials with. Just practice your L-cancels.
-Use your tilts and jabs. Out of the three tilts, forward tilt will be the one you will be using the most as a form of approach. These will consist of your ground game most of the time because they have little to no lag. Sure it seems simple and easy, but it's HIGHLY effective.
-Learn how to edge-guard. Up tilt, down-angled forward smash/forward tilt, edge hogging, standing homing missiles, charged/uncharged shots, running off to sex kick.
-Learn the advantages of the wavedash. You need it for spacing. Wavedash away from an attack and then punish your opponent with a forward smash. Wavedash to chase your opponent's roll/tech-roll and punish with them with down smash/forward smash/grab.
-Learn what you can do out of your shield: Up-B out of shield, wavedash out of shield to down smash/ftilt/up tilt, jump out of shield into sex kick.
-Common habits I see inexperienced Samus players do and that you should avoid: Spamming the dash attack, sex kick, and smashes [you will get shield-grabbed/punished a lot]. Spot-dodging too much. Trying to grab too much. Not shielding enough. Not sweet-spotting the ledge. Trying to shield-grab [her shield-grab is too slow, wavedash/up-b out of shield instead]. Basically, doing any of these things will get you heavily punished. So don't do them.
Samus is best played passively and receptively, but you have to bait your opponent and quickly capitalize on his mistake or a laggy move, then tech-chase/edge-guard. And keep in mind priority, spacing, and the lag time for your and your opponent's moves.
Hope that helped.