How to defeat the Pokemon league?

You should train your Pokemon to at least level 55 or higher. You'll also need Revives and Max Revives as well as Max Super potions and Full Restores. You shouldn't have much trouble battling them if you've trained your Pokemon that much and have enough items.

I recommend to have your Pokemon to be around level 55, the reason why I recommend this it's because the final trainer you will have to battle which is Ghetsis and his Pokemon is around level 52-54, which means he will be the hardest out of all the trainers to battle against. So if you want an easier go at beating him level your Pokemon to around level 55 so you will have the upper hand. Oh don't forget to stock up on revives, full restores and possibly full heals so you don't have to use up full restores on Pokemon which don't really need them.

Have the team of
Your starter (Emboar is the most helpful)
Haxorus
Krookodile
Electross
Archeops
Ferrothorn

Hope this helps

If you want to beat the elite four then get your Pokemon up to lv 100 I have friend who entered with lv 95 and barly made it out so get alot of heals

Pokemon league is hard my hightest Pokemon is only lv 42

The Pokemon I have used is victini superor samurott emboar tranquill and audino

Get a beartic, raise it 2 a high level (mines a 58), & have it learn shadow claw & icicle crash 2 beat caitlin easily

You need serpirior

U need to get a level 100 arceus to beat the Pokemon league because I have a level 90 emboar and I did not make it. When I tried arceus I made it.

Try to have as many rare candies as much as possible if you want to raise them up quickly. You can buy them at battle subway with your battle points, but make sure you have a lot of BP. It will be a slow process but worth it.