Easy.
Get a Golbat and train it.
You can't find "strong Pokemon". If you want a Pokemon to be strong, you need to train it.
Torchick is a good Pokemon if you train it right anything should work
Trade one from Pokemon colosseum or get a chikorita from either Pokemon emerald or Pokemon xd gale of darkness then train it to level 16.
You an train Pokemon in the grass
get a pokemon, then you train it, get it really strong, and beat th ecrap out of all the 7th leader's pokemon. Its easy.
you train them
train your pokemon
Yes, you can
Train a Chansey and will evolve.
Easy.
Get a Golbat and train it.
ANYWHERE
easy stroomish
You can't find "strong Pokemon". If you want a Pokemon to be strong, you need to train it.
No you have to train surskit to level 22.