Pokémon battling strategies that I used when I was younger vs. now
Younger me: Have some moves that are strong against the Pokémon's weaknesses.
Me now: Look at Smogon movesets and see what I can do. Otherwise, use a Attack/Special Attack-raising move and a move of the attack category that the attack-raising affects.
Younger me also only used offensive attacks instead of moves like Stealth Rock or Healing Bell. Physical and special moves were both used in a way that isn't a good strategy.
I was such a terrible battler back then, but I could still beat my friend that battled me on Showdown Battle Simulator.