Choking is usually a result of you taking a match not as seriously as you should, going auto-pilot or being nervous. You tend to do poor options and find yourself in desperate situations when you get pressured. I used to have a lot of trouble with this, but I've developed ways around it.
Over the past few months I have found a few ways of countering choking, and when put together I usually find I play near my peak, or at least what I
think my peak is.
1 - Watch your opponent's character, not your own. Although this sounds really weird, once you get good at it you'll never worry about spacing issues and wrong moves at the wrong time again. When you watch your opponent's character, your brain will know where you are on stage. When your character comes into range, your brain will know you can do something. Not only are you becoming much more aware in virtually every situation by watching your opponent and seeing what they do, but you are going to be able to space yourself and react to it properly with the right attacks at the right time.
2 - Narrate the game in your head. It forces you to think in all situations. Every match, think to yourself that the soothing voice of D1 (or really any commentator, really) is analyzing your play, and you'll tend to do the same.
3 - Be confident and know your options, and mix up said options. Test your opponent. Do the 'PC Chris' test and run up to opponents and shield to see what they do. You can end up getting crazy kills just from finding one opening, so find their weakness and exploit it by using all your moves in a link that works. You need to know your character(s)'s hitboxes and knockback, so I suggest you look those up.
Personal example - I was watching a Marth player recover and this Marth decided to forward-B near the edge. I noticed early on that there's a lot of end lag after the hitbox comes out, and since I was watching his character I noticed Marth's head protruded past the ledge. I quickly wavedashed over and hit him with an F-smash, and he wasn't able to recover. One small mistake from him was all it took for me to take the stock and ultimately the game. This was because I saw an opening though watching my opponent, I knew my options and what I could do, and I was confident enough to go out and do it.
Another example of one mistake is all it takes.
Just like Prog said in the Smash Doc, "
Smash is jazz. Everything else is classical music."
For another metaphor, Smash is the opposite of a multiple choice test. There isn't just one answer that is the right answer to one question. This game forces you to adapt, and when you are playing you have to take in tons of variables to account like percent, stage position, if you have a double jump, character direction, stage, character, match ups, etc. One option may work in one situation and not in the next. Players have to constantly adapt and figure ways around each issue. the best way to overcome problems isn't always to play the game more, but rather research and study matches. (And also grind tech skill, but that's something I'm not going to get into atm)
Simply playing Melee for hours on end with the same people isn't necessarily going to help you improve. You should watch matches of top level players sparring off with other players and see some of their answers to how other players approach. Don't just watch top level players go at it though, watch top level players destroy low level ones, and see what you are doing wrong. See if you can find the other low level player's habits by watching the match. See if you can figure out and predict what they are going to do, and see if you can copy the pro's way around it or come up with your own way to counter it. While this may seem flow-chart-esque, I also find it very natural. I recommend trying it to people who are having trouble.
