Netplay in my opinion has a completely different meta than playing IRL. I find it harder to do a lot of things over netplay like tech skill and punishes. There was actually a case where I played with a marth over netplay and I would get 4 stocked because I had trouble punished forward smashes and counters. He came to my town and we played and it was the other way around (I punished everything and destroyed him). My advice might work on netplay but I have only really used it proficiently in real life matches
TLDNR - Netplay is different from IRL but heres what I do IRL, maybe it will help
Depending on who you are fighting, approaching can be good or bad. Against characters like marth, I generally try to limit my approaches because approaching can actually give your opponents an advantage (It is harder for marth to get a grab etc if he has to chase after you). For approaching though, I like to mix up between laser approaches (learn the distances you can travel with 1 short hop laser and different options out of that like ftilt, fsmash, aerial, etc). If there are platforms you can also fake people out by jumping up like you are going to land on a platform then fall through and use an aerial. You can also go onto the top platform, drop down, then double jump to waveland back on it. This can be a good mindgame so your opponent doesnt know when you approach. Running towards your opponent and wavedashing backwards to make the opponent miss then wavedashing forwards with a punish will always be a great option too.
Other advice: Throw in some dash dancing before approaches. If you always go straight for your opponent, they won't be scared of when you are going in because they will know its coming. When your opponent has no idea of what you are going to do next, they usually play a lot worse.
