I have a bit of a headache, so I hope this doesn't come out too jumbled.
IVs (or Individual Values) are the part of your Pokemon's stats that are set once the Pokemon has been generated (as in, hatched, if you're breeding). They can differ from Pokemon to Pokemon of the same species, so not all Pokemon have the ability to reach maximum potential.
You can check a Pokemon's IVs in
Kiloude City, once you've beat the Elite Four. He'll be the purple-haired guy on the left side in the Pokemon Center. He'll tell you which of your pokemon's stats are good, and which aren't (if your pokemon has a low IV, he'll tell you you won't get very far with it). You're looking for an
Outstanding Pokemon whose stats
can't be beat.
People who breed competitively tend to try for at least 4 good stats, and which 4 they want depends on the kind of pokemon they're breeding. I try to go for 5 good ones. 6 is also possible, but very annoying to get.
Passing down IVs has been made easier in X and Y thanks to the
Destiny Knot. Be sure to have one when breeding. It takes 5 random IVs from the parents and guarantees that they'll be passed down. The more good IVs the parents have, the easier it will be to breed upward.
Ideally, you'd start with two Pokemon with at least 2 IVs each, and both of those having two different IVs. Breed those two until one of the parents have 3 IVs, and depending on which IVs they are, replace one of the parents to increase your chances of getting more IVs. You replace the parents whose IVs the child already has, since you would no longer need that parent. Keep going until you get a Pokemon with 4, 5, or even 6 IVs, if you want.
Natures are important as well. There are neutral natures, which won't affect a Pokemon's stats one way or the other. However, many natures will add to one stat, and take from another, which is why people try for Pokemon with specific Natures. You can breed for Natures before breeding for IVs or after. You pass down Natures by using an
Everstone, which passes down the Nature of the Pokemon who's holding it.
People who are breeding will have one Pokemon hold the Destiny Knot, and another Pokemon holding the Everstone, to ensure that stats and natures are being consistently passed down.
Another thing that gets passed down is a Pokemon's
Ability. Having the right abilities on a Pokemon is important to battles because they have very important effects. I believe getting the mother's ability to pass down is easier, but the child can still manage to inherit the father's ability. Be sure you get the ability you want on your pokemon before investing time into raising its EVs.
EVs can be switched around depending on what stat you want to invest in for your Pokemon. Each Pokemon gets 508 EVs total, with 252 being the maximum amount of EVs you can invest into one single stat.
Ideally, you start EV training a Pokemon that's never fought anything before, so that none of its EVs have been raised. If a Pokemon has EVs in a stat that you don't want it to have them in, you can get a
Reset Bag through the super training window by punching the default bag. This could take some time, but Reset Bags are very handy. You can tell what stats have been raised on a Pokemon in that same Super training window. The darker green area are the base stats, and the yellow part represents the EVs. If there's yellow in stats you don't want, use the reset bag.
From here, there are two ways to raise EVs.
Super Training involves using the minigames with the soccer balls. It's easy to tell which one is which, since they'll be labeled with the stat they increase.
You can also do horde training by fighting certain types of Pokemon. Each Pokemon you fight will raise one kind of EV that it give you. Fighting hordes gives you 5 at once (sometimes 10, since some pokemon give 2 EV points when you defeat them).
Guide for training with Hordes
Getting another Destiny Knot in case you lose yours
Getting more Everstones
Pokemon Natures
Pokemon Team Builder. Useful tool for building a hypothetical team quickly to see if it works out, so that you don't end up investing a lot of time and end up having a team that doesn't work out for you.
