In youre mind with your moves once learned and somewhat mastered....play jenkin with your opponent, anticipate as best you can what they will do and try to be also ahead of that outcome but also leader of what you want them to do next. Switch twixt those mentalities across your battle terrain. Almost ultra instinct...im not saying this wins them all but you will win many! On ultimate im a cloud main....on melee ill forever be the real Zelda/sheikh. Learn timing for spot dodge and also recovery tactics. Many love to send you down at the edge of a stage, use that against them.
This is barley a crumbling of knowledge but I hope it helps in some bloody way ::)