First you must get all 8 Badges, then i would get a really good team.
The first Elite trainer is Lorelei who uses ice type, so use electric.
The second is Bruno with fighting type, so flying/psychic should do the trick.
Then there's Agatha with ghost/poison/dark pokemon, but surprisingly, psychic/ghost is very effective.
And Dragon Trainer Lance who uses well, dragon! To beat him use dragon/ice.
Then there's the Champion (your rival Gary or whatever you named him). Hes' got Pidgeot, either Blastoise, Charizard, or Venasaur, Arcanine, and some others too. Use whatever you got!
beat the Pokemon league
you cant
Face the Pokemon League again
Left of Viridian city is a path leading up to indigo plateau. That is the pokemon league.
Then you have to get all the Pokemon you can and try to get all the Pokemon.
beat the Pokemon league.
Catch all the Pokemon. credits are rolled if you beat the Pokemon league
You have to beat the original champion in the game
the Pokemon league and maybe cerulean cave
Well my team was Wigglytuff charizard
You can beat the Pokemon League it is just one of the harder Leagues than in Pokemon Emerald or Diamond.
he's at the Pokemon league.