Well, don't fret since in this generation it's a little easier. You can now pass down IVs with the Destiny Knot - which can be quite helpful, especially for Hidden Power reasons.
Since there are 186 possible combinations of IV sets, thankfully Fighting is one of the most common types of Hidden Power, tying with Grass and Bug!
There are 14.53125 possible Fighting-type-Hidden-Power IV sets.
And, the formula? It's simply that all IVs have to be an even number (as opposed to odd). Yep!
So, when you try to breed, make sure you take note of your couple's IVs.
- That both of the couples have mostly even-numbered IVs. (The more IVs that are even, the better chance of a Fighting-Hidden Power)
- Make sure one of the parents (mother of father) holds the Destiny Knot.
If you hold the Destiny Knot, at least 5 IVs between both parents will be passed down to the baby. These will be random IVs, so just make sure that your couple has as many even IVs as possible.
Unfortunately, each Pokemon does have 6 IVs, meaning that there is still a possibility that there could be an odd IV. However, it's a half-half chance that the remaining IV could be odd or even.
When finding your breeding couple, to check their IVs use this. No majorly inaccurate things have been reported, so it's a reasonably good calculator. Make sure you don't train up your couple. Unless you know the EVs you're giving your Pokemon, just make sure you catch them but not train them. All newly-caught Pokemon have 0 EVs in each stat.
If you have any more questions, just ask me, I guess. x)
Hope I helped. :)
Source: Experience, this and this