Train them............
you train them
if you want to level up your pokemon faster. give the pokemon you want to level up an exp share but it at the bottom of your pokemon list and battle and beat the elite4 in succession over and over until it is at the level you want it to be.
take a weak pokemon to the elite four
YOU HAVE TO GET ALOT OF rare candy.
Its the same either way.
Try using Rare Candies for easy levelling. :)
To level up pokemon quicker you must defeat higher leveled pokemon for one also if the pokemon your training was traded to you it will receive boosted experience points which help level up your pokemon even faster. If your pokemon holds a lucky egg item they will receive this kind of boost as well and if you give this to a pokemon that was traded to you it will receive even more boosted experience points.
Giving a Pokemon an experience share at a low level while other, stronger Pokemon fight will level up to a strong enough to level to fight well and train. You can also level them up faster by using Rare candies either by using cheat codes and/or action replays or saving up Rare candies found throughout the game. The best way to level up your Pokemon is to fight constantly although it is not the fastest way.
A shiny Pokemon is no different than a regular Pokemon in stats or growing levels.
There are probably some game-shark codes that do level your Pokemon up FASTER in the daycare. If your Pokemon is in the daycare it will gain EXP. with every step you take.
yes by battling the elite four