Dittos in Safari zone have 2 IVs perfect, and 1/32 chance of getting one of 4 other IVs perfect, so 2/17 chance of getting 3IV ditto. Capture couple dittos. Make sure that they have different IVs. Say one is HP, Att, Def, and the other is SpA, SpD, Spe. (though any combination is good as long as there is 6 different perfect IVs spread over 2 pokemon)
First, get a good natured pokemon - you can do it after capturing enough dittos (one in each nature), having the ditto hold everstone, and breed it with the target pokemon.
Breed one of the dittos with Destiny Knot with pokemon you want to have 6IV. Wait till that pokemon has 3IV.
Then breed it with the second Ditto, and when you'll have 4 IV poke substitute it at the breeder. then if you have 4 different IV of different gender (that add up to 6 different IVs, take out ditto). If you have 5/6IV pokemon of any gender, substitute as appropriate.
As always, one of them holds Everstone (to pass its Nature), and the other holds Destiny Knot.
You have about 3/32 (don't recall the exact number) chance of getting good Ability pokemon once you have two 6IV breeders. Of course keep your 6IV male breeders for each egg group, as they speed up the breeding process incredibly.
Hope this helps
