I'm glad that you posted that Sid, cause with information like that I might be able to help you improve. EVERYONE who plays smash will hit a plateau at some point, but you just gotta tough it out to make it to the next level. This usually happens after someone learns all the basic tech skill (wavedashing, l-cancelling, shffling, and some character specific stuff). People tend to hit plateaus when they run out of tech skill to improve on, and if you aren't playing fox, falco, or Ice Climbers, you can hit it pretty fast.
Anyeays, here are some things that you could look into to help you out:
@wavedashing
Wavedashing really doesn't increase the speed of melee much. Sure, for characters like the ICs, Luigi, and Mewtwo it speeds them up, but for most others with decent wavedashes, it just adds the option of going backwards without turning around. You need to actually work on trying to figure out what is causing your losses as opposed to just pointing your finger at the wavedash. If you can, record a video or two. Just use a VCR or something. Rewatch the video and find out what went wrong. If you felt like you were helpless during the entire match, it could be because your opponent was playing smart, or they were incredibly technical with their pressure game and you didn't know how to overcome it. Another very likely scenario is that you were so demoralized by your opponents wavedashing that it destroys your ability to play the game. If you go into a match thinking you will lose, you probably will. You gotta overcome those mental obstacles if you want to take your game further.
@mindgames
Honest to goodness, you should learn how to manipulate the lowbies with smart play and move on to the big fish. If you try to learn mindgames against veterans it is much much harder to pick up on, as they make less obvious mistakes. Learn to pick up on patterns, behaviours, and etc with some of your casual chums. You don't have to **** them for it if you want to keep it casual, but keep tabs on them. Pick up on where they tech roll too, or if they use their second jump as fast as possible after an up throw. Once you have a good grounding in observing stuff like that you can learn to spot some of the more subtle habbits of better players.