I'm late on this, and most people have already said what I would have - but I'll say a few things anyway.
You need to put up your shield ALOT more. I know you want to go and show your stuff at SMYM9, so listen to this piece of advice. In the majority of your matches I saw you getting hit by almost everything your opponents threw out. Their approaches and some other random smashers mostly. If your opponent runs straight at you with a nair and is extremely obvious about it, don't let it hit you. Don't try to stand there and beat it with your moves all the time. Don't try to tech skill your way in and out of situations that don't need tech skill/shine. Just stand there and shield, then grab. Boom, thats what like 2 uairs on Pika sometimes? I'm not saying you were doing all that I just mentioned, I just want you to start thinking of the more fundamental, effective, PC-Chrissy ways of doing things. You have potential, but your thought processing mid-match needs to be a bit more refined. Pay attention to how your opponent is moving around. Attack when needed and escape safely, put up shield and work out of it in different ways to keep your opponent confused. i.e.: Rolls/sidesteps aren't enough, WD back out of shield and reset your position somewhere else on the stage for more breathing room, or WD in and CC an attack you expect is coming (if he has a somewhat predictable pattern of attack)
etc etc. You know what I mean.
Man I ramble alot.
Vs. Pika: I don't say this very often, but be LESS patient at the ledge. You just sat there a bunch of times and let Pika upb right back on the stage. Jump off and bair and you might hit. If that doesn't work, the Pika will have landed on the stage in lag (because you were holding the edge earlier), so go and punish that skank with grabs and stuff.
Your combo game seems to be developing. Just try not to be too impulsive and follow your opponent off stage to extend one. You did that one too many times vs. Dk and it got you edge-guarded.
Use the edge more for invincibility and shine spikes. Above all, slow your game down and just think more. Take a step back and you'll notice a lot of the more intricate details about the game. Certain moves you were mis-spacing slightly, ways you could have used the platforms to approach (in relation to your opponents positioning), easier ways of edge-guarding that didn't involve running off for non-invincible shines. I have this feeling that everyone in melee has had, or will have, a single instance during a match where everything will just come together and flow. You post on here pretty often and take a bunch of advice, so I have a feeling you know what to do, and how to do it. Applying it consistently seems to be your only real issue, besides some obvious tourny/play experience.
-Stay alert, don't miss easy techs or opportunities to punish opponents lag.
-Don't run in blindly, have a plan at least 70% of the time and I guarantee the moves you want to hit with will actually hit.
-Remember match-up specific information, and don't be afraid to spam the fundamental **** stuff, because it almost always works. (invincible ledge stuff, uthrow uair, grab in general for free hits)
-Pace yourself when you are down stocks or in a tight situation/near an edge. If you take a step back and think about the situation properly, you can avoid making really obvious evasive decisions like rolling towards or jumping oos quickly.
Good luck SMYM9!
lol it felt like I was just regurgitating a bunch of information. Sorry if it all got too repetitive. later man!
