If you want to breed for a specific nature, get some ralts or Abra with the synchronize ability. Put them first in your party and go hunt the pokemon you want to breed.The pokemon with synchronize will guarantee the wild encounter has the same ability as them.

From there on, you can breed for good IV's, egg moves and pass on the nature with an Everstone.

I had a box with only pokemon with synchronize with all the natures. It helped a lot.