Try to get so good at tech skill that most of it becomes second nature. Then, when you're playing someone, try to watch your opponent more than you watch your own character. When you're really good at tech skill, you don't have to spend as much of your mental energy on timing things, leaving you with more mental energy to use on paying attention to the match. Try to take something away from every game you play. A loss isn't a total loss if you remember how to better tackle a certain situation. Pay a ton of attention during matches and try extremely hard. If you pay attention to how your opponent landed hits on you successfully, then when your opponent is about to try his same tricks again, your memory will kick in and you will be able to predict his movement.
There is a difference between the moves you have the technical skill to pull off, and the moves you have actually worked into your game. You may know how to pillar combo, but you won't be able to pillar combo in a real game unless you have figured out ahead of time what situation you want to do it in (though after you pull off a move enough times, you'll be able to spontaneously decide to do it in a random situation). What I do is I list out in my head all the literal options I have for each situation. For Falco, it might look something like this:
Neutral game options:
Shorthop lasering
Nair approach
Predict opponent's attack and shield grab them
I'm below the opponent:
Jump and Bair them
Jump and Nair them
I've grabbed the opponent:
Down throw into up tilt
Up throw > Jump > Bair
After creating your mental list of options, remember it while you play some games. Whenever you're in a situation, like say, neutral game, you would think to yourself: "Do I want to A. Shorthop laser, B. Neutral air approach, or C. Try to shield grab them?". As you play more games, you'll be able to run through your mental list of options faster and faster. And it will take less time to think of all your options and figure out which one you want to do. Then, once you've played enough such that you've used all your options a lot, applying X option to Y situation will become reflexively ingrained in your mind, and you will be able to quickly figure out which option you want to do, thus using up less mental energy and allowing you to use more mental energy on studying your opponent. After you have played enough games to practice applying all of your moves/options, add more to your list. It might look something like this next:
Neutral game options:
Shorthop lasering
Nair approach
Predict opponent's attack and shield grab them
Wavedash forward into F-tilt
Shorthop Nair > fastfall > L cancel > shine > Jump > Dair
I'm below the opponent:
Jump and Bair them
Jump and Nair them
Jump > Shine > Jump > Bair
Up tilt them
I've grabbed the opponent:
Down throw into up tilt
Up throw > Jump > Bair
Up throw > wait > Usmash
After you add a couple of things to your list of moves, play some games against real people until you are able to incorporate all of the moves on your new list. Then add a couple more to your list, then play more games until you can incorporate those. Keep repeating the process and you will soon get a lot better.
Remember when I said this above: "applying X option to Y situation will become reflexively ingrained in your mind, and you will be able to quickly figure out which option you want to do"? I wouldn't take this too literally because if you always apply a certain move to a certain situation, you will get predictable. What I mean is to figure out when it's generally best to use each move and apply that knowledge. When you get really good at tech skill, applying all your tricks in real games, and making quick decisions on what to do, you will be able to alter when you do your moves to counter your opponent's playstyle and out-mindgame them.
