I need to fill my pokedex in BW
1 step= 1 exp.
A way to level up Pokemon faster in the daycare in BW is to go to Gear Station in Nimbasa City and run in circles in a path with no people. If you put something to hold your B button and down buttons down and leave your DS on and charging overnight, your Pokemon would have gained quite a few levels.
Well, as you might know.
Pokemon get 1 Experience per Step in the Daycare, what I do if I really want to level a pokemon up via Daycare, is go to Tubeline Bridge, and Get on your bike and ride back and forth.
Although, Just fighting the pokemon league with an Exp Share works better than the daycare, thats about the fastest way to level up with the daycare.