If u don't have action replay, put lucky eggs (obtained from wild Chansey) on your Pokemon.
If u do, this is a good code:
94000130 000002FF
62106FC0 00000000
B2106FC0 00000000
100458DC 0000FFFF
D2000000 00000000
It gives u 65535 exp points for wild Pokemon and 98302 for trainers. But if u hold the lucky egg, u get 98302 points for wild Pokemon and even more for trainers! Hold R when the Pokemon faints.
keep battling Pokemon and people
Train your pokemon.
level 100
level it up to level 21
any level up to 100
level it up
Get the Exp. Share and give it to the Pokemon you want to level up. Be sure to put in your first slot. When you find a battle substitute your Pokemon right away for one that is really good. Then make your opponent faint. Your Pokemon should earn alot of Exp. points. It will then level up!
level up or action replay
You have to get Piplup for the starter Pokemon and level him up or trade for it.
level your Pokemon up to 80
Level it up to level 34.
you battle and level it up