I'm surprised no one has linked the SSBM Advanced How to Play videos yet, I can't post the links because I haven't posted enough in the boards

, but just search "Advanced How to Play Melee" in Youtube and you should find it.
Before you read on, just know that I am by no means a highly skilled player, I too am trying to get into Competitive Project M, but am just a little farther along the path than you are, krains123.
As far as practicing techniques, you really just need to play and practice! Go into training mode, and just practice something for awhile. Work on your short hop, wavedash, waveland, your SHFFL (be sure to practice both when you hit and when you miss an opponent as the timings are slightly different, I've heard hitting the pillars on Shadow Moses Island is good for this). You don't have to spend all day on it if you don't have the time; just a few minutes here and there will help you immensely. Don't get frustrated if you can't get something down, just keep practicing and you'll eventually get the muscle memory down.
If you can, find some players that live near you, and play with them. Do NOT focus on winning, focus on utilizing the techs you've been practicing. Tell yourself stuff like; this game I am going to be sure to L-cancel every aerial, I'm going to really utilize wavedashing this game, etc. Don't judge your performance based on wins and losses, base it on how well you executed those goals. Did you hit those L-cancels? Did you flub all your wavedashes? And again, don't get frustrated if you start messing things up that you've got down in practice, doing something in training and then doing it playing a real opponent is totally different.
And for things like wavedashing, dash dancing, etc., you will probably use them in the wrong situations and get punished. Don't let this discourage you from using those techs, just make a mental note of when you should or shouldn't do things. No one learns wavedashing one day and then can utilize it to perfection the next, you will learn when you should use them as you play.
Ask your opponent if they noticed you doing anything predictable, or that was easily punishable. Ask them about their play style and why they do what they do. If possible, record your matches so that you can go back and analyze what you did. I personally have not had a chance to do that yet so I am probably not the best person to tell you how to analyze your matches, lol.
And finally, watch some matches of some high level players that use your character. It might be difficult to follow at first, but watch to see how and when they utilize different techs and different attacks, and try to incorporate that into your playstyle. There's nothing wrong with mimicking someone else's playstyle in order to make your style better.
I hope at least some of this helps you, and good luck on your journey into competitive Smash!