I think the most important and best way for you to improve, is to watch what your opponent does, before you make any move. I see that you very often decide to do AAA out of your QD or Aether after hitting someone upwards. However, you've decided on it long before you actually do them. You do the QD just because you want to go AAA afterwards. This leaves a big risk. After watching just the first match I could pretty much predict where you were gonna go next and what you were going to do there.
So my advice is, try to hold yourself back on attacking. Try to do more stuff without doing any attack, then watch how your opponent reacts and then try to hit him. Like, if you would do the AAA after the QD, I'm sure that Marth would come running at you, you could always do your AAA at that time. This stops you from having certain paterns in your attacks (missed QD > AAA, hitting with QD > Aether).
Also, in the first video I saw you using fsmash a lot in the beginning. Fsmash is a move you should use later in the match, if you can read your opponent perfectly. In these cases, if you wanted a strong move that could be charged, a usmash would be better. If you just wanted to add damage, try shorthopping your fair.