Your first step should be to obtain as many Dittos as possible with at least 2 max IV's each, covering all the stats at least once. You can find wild Ditto's in Pokemon Village. They are quite common. Another way to get Dittos, often foreign ones that others have gotten from Friend Safaris and decided they don't need, is to use Wonder Trade A LOT. The significance of them being foreign is that it will raise your Shiny rate when breeding a Pokemon from your region with one from a foreign region via the Masuda Method.
After you have acquired your Dittos, you should go through the process of deciding on Egg Moves, if any, and getting the Pokemon you want to breed with the Ability you want and the Nature you want. For a Hidden Ability, you will require a Pokemon of the specie in question with the Hidden Ability. Preferably, it should be female, providing a higher chance of passing it on to the eggs. For Nature, have the Pokemon with the Nature you want hold an Everstone. This guarantees that the eggs will hatch with the Nature in question.
Now you're finally ready to start breeding in IVs. It's usually easier to start by using the Power items you can buy at the Battle Mansion with BP. When a parent Pokemon holds one at the daycare, it guarantees that the corresponding IV of the Pokemon will be passed down to the eggs. By this method, you can immediately pass on the first IV, and get the second and third IVs relatively quickly. You may need to go through a lot of eggs though if you are using a Hidden Ability, because you are not guaranteed to get it even with both parents being of the specie and both having the Hidden Ability. Again, females pass it on 3 times more often than males, so you will most likely want to hold out for a female child with all the IVs.
After you get 3 IVs injected into the Pokemon, it is usually more effective to switch from the Power items to the Destiny Knot. The Power items force a single IV to the offspring, while the Destiny Knot chooses 5 IVs from the combined total of 12 possible IVs of the parent Pokemon. So for example, for one egg it will use the Father's HP, Def, and Spd and add the Mother's Att and SpDef, leaving 1 to be determined at random.
And that's everything there is to know about IV Breeding!
Just understand that it might take you a really really long time to get past the "4 IV barrier". I ended up breeding 8 Speed Boost Torchics with 4 IVs and a lot of 4 IV Blaze Torchics before finally getting a 5 IV Speed Boost. It's taken me 2 weeks to get 3 Pokemon with 5 IVs, 2 with Hidden Abilities. Still need the other half of my team.
