I don't use Ditto if I can help it because it slows egg production and makes it harder to pass on IVs.
This is my general strategy for MMing:
- Breed a female parent with the desired nature and as many desirable IVs as possible. By selective breeding and rebreeding with a power item + everstone, it is easy to get 3 IVs onto a pokemon - 4 if you're patient. (Except for genderless pokemon, since it's unlikely you'll find a ditto with good IVs - I tend to lose patience with those.) I start with Dittos and pokemon in the same egg group if I need to transfer particular IVs.
- Aim for a foreign parent (either same species, or compatible species if you need egg moves) with as many max IVs as possible. Put a ditto of your region on the GTS and request a lvl 1-10 male pokemon. Choosing a low level means the person on the end will probably breed it, and you have a good chance of getting one from a breeder who's doing the same thing you're doing. Repeat until you get one you're happy with.
- Put a power item on the male and an everstone on the female and start breeding. If you hatch a better version of the female (with dream world ability, if you're gunning for those), then breed with that instead.
Of course, you can reverse the roles of the males and females. I usually breed the female myself for 2 reasons: I can ensure that I get a Dream World ability AND the nature I want, and the gender ratio for a lot of pokemon is 8-to-1 in favor of males, meaning it takes longer to find a foreign female. If your biggest concern is passing on chain-bred egg moves, then you would breed the male instead. (Also, I recently realized that the everstone can go on either parent - I don't think that held me back too much.)