In the early play-throughs of yellow i had 2 methods:
1. Drawing upon the wisdom of a friend, I would spend the entire day grinding my Pikachu to level 20 so that I would learn Slam. Pikachu would remain overleveled in comparison to my team for the rest of the game.
2. Use and abuse Double Team and Tail Whip to lower the defense in order to turn a scratch into a dent with Quick Attack. Very luck based and needed I Potions for security.
1. Drawing upon the wisdom of a friend, I would spend the entire day grinding my Pikachu to level 20 so that I would learn Slam. Pikachu would remain overleveled in comparison to my team for the rest of the game.
2. Use and abuse Double Team and Tail Whip to lower the defense in order to turn a scratch into a dent with Quick Attack. Very luck based and needed I Potions for security.