You need to get the basics down better. Practice till you never miss a WD out of shine. Additionally, work on being faster. I noticed minor things, like when you run off the edge of a platform to catch up with your opponent, you don't fastfall. Or when you hit him with a full-hopped nair, you don't fastfall. Pay attention to these things, and generally try to always be doing something. You don't want any moments when you're waiting on your character to finish falling or something. Chain one movement directly into the next.
That might have been unclear. Tell me if you need better explanation. Also I'm not very good either, so I'm sure others will have better advice.
EDIT:
Actually, it looks like you hardly ever fastfall. Make that a priority. Also, don't miss l-cancels. You weren't that bad about it, but you want to be at like 99.95% consistency eventually.
