Three step program. Work on those reaction timings, work on those reading skills, then shave off whatever makes you crap at the game.

It kinda depends where you are in terms of skill level, and there are a lot of aspects that go into your performance. 1 - Find your weakness. If you aren't sure what your weaknesses are, find an opponent and analyze the times where things don't work out for you. Try not to be too broad like "My neutral game needs work." Make sure you narrow it down. 2 - You might want to find a video to see why other people don't have the weakness that you have. 3 - If it has something to do with tech skill or lack of consistency, then train independently. (on 20XX training hack pack preferably) 4 - apply it to actual matches One really important concept in melee is adaptability. If you know exactly how to adapt in every situation, and your execution is flawless then you become unbeatable. Also, watch some SSBM tutorials. https://www.youtube.com/watch?v=uXvKpe5MP0s&t=313s