You are asking the wrong person about competitive battle. I only know how to breed 'em. You'd have better luck seeing if there's any sort of guides in the battling subforum: here.
Honestly, I used this guide when I learned how to IV breed. tl;dr is you use the Destiny Knot, and 5 out of 6 IVs will be inherited from either parent. As you get parents with better IVs, you swap 'em out until you get the Pokemon with a perfect IV spread.
The process goes 10x faster if you have a 6IV Ditto. I'm not sure how easy they are to find on PC. I got mine from friends.