welcome
learn to WAC as well as it helps tons with recovery and kills
learn to love your nair and utilt; they both break sheilds exceptionally well. If you do catch someone with a nair then make sure to fastfall into the ground to autocancel the last hit (with knockback). If you do this then you can instantly catch them in an utilt for extra damage or usmash/dsmash for a kill. It comes in handy a lot.
learn to play well with nolimar (pikminless olimar), as you will find that sometimes the little buggers will abandon you. It also helps you to learn to vary your playstyle by tilting more often.
Also when you are practicing using upb offensively, short hop it and then fastfall back to the ground and you will land lagless. It also works well if you upb up onto a ledge. If you upb while grounded it is very laggy and punishable.
best of luck, my friend in olimar