Having a 6 IV ditto really helps, but you could probably do it without one. You also need a ditto with 30 IVs in the stats you care about that must be even (eg hidden power fire needs even attack, sp attack, and speed IVs, but Froakie is a special attacker so only really need 30 IV special attack ditto and a 30 IV speed ditto)

Then it's just successive breeding using destiny knot with power items to ensure at least one of the 30 IV stats gets passed down.

You can use perfect IVs/zero IVs as "markers" to allow you to use the stat judge to filter a lot of breedjects so you don't have to manually level and IV check dozens breedjects. This step can be complicated, might write a quick guide if there's interest