Been awhile since I fought it and I don't remember what I did tbh. I think status moves are your best bet. Try getting a pokemon that can learn toxic and stall it out, or get pokemon that are resistant to the attacks it uses and try to chip it down
Is it out of an egg or no? If it isn't then it's about what above person said, if it's from an egg, I think it's already predetermined when you pick it up
Dittos aren't really that good since it would be hard to get good iv's I think most people usually breed with the same species pokemon. Just a friendly tip!
Do you have any specific powerhouses you want?
Edit: I guess I took to long to answer about breeding.