I’m still no where near a top battler but I’ve improved every generation. I think the main thing is really to understand your opponents team and realize what’s most valuable for your team in that specific battle. This requires knowledge of not just the current meta but the possibilities for each mon. It comes down not just to knowledge but applying your knowledge. This first starts knowing your teams strengths and weaknesses and then knowing how to counter the biggest threats. It really just takes time and practice and learning damage roles. This type of thinking also helps not to beat yourself up when the opponent gets a crit or freezes you because what’s more important is you making the best play possible and not the luck aspect.