Let's start with the basics, what are EVs? EV stands for Effort Values. Except in facilities such as the Battle Subway or when battling a friend, whenever you cause an opponent's Pokemon to faint you get a certain number of EVs. EVs can be for any of the 6 main stats: HP, Attack, Defense, Special Attack, Special Defense, and Speed. 4 EV points in any of these stats is +1 for their actual stats. For example, let's say I get 4 EV points in Speed for my Pikachu. Let's say that before that its Speed Stat was at 155 (just making this up) anyways, after getting those 4 EV points in Speed, the Pikachu's Speed stat will then become 156. Just remember that every 4 EVs in a Stat is 1 real Stat Point. If done right, these could really add up.

HOWEVER! There are limits. A Pokemon can only have 510 EVs Max. And it can only have 255 in one stat. Because neither of these are multiples of 4, some EVs are going to end up being wasted. Even at maximum EV training efficiency you'll still only have 2 EV points that will never be usable for anything. Because of this most people recommend distributing your EVs the following way: put 252 EVs in one stat, 252 EVs in another stat, and 4 in a third stat. Just decide which two stats are most important to the Target Pokemon and a third stat they just need a tiny push in.

There is no way of checking exactly how many EVs you have in one Pokemon. You can only determine whether or not you've used all 510 EV points. In Black and White, this is done by talking to a lady in Opelucid City. If your Pokemon has not used up all its EV Points then she will say "Your [First Pokemon in Party] needs to try a little harder..." But if you have full EVs, then she will say "Your [First Pokemon in Party] put in a great effort!" this is where the term Effort Values comes from.

The best way to calculate how many EVs a Pokemon has is with a pencil and paper to keep tally. Let's use an example. Patrat gives 1 EV Point for the Attack stat. So if you were to EV Train a Pokemon for Attack, let's say Tepig, you would have to faint 252 Patrats with that Tepig. Obviously that seems like a bit too much of a hassle but there are plenty of ways to speed up this process.

Vitamins. Vitamins give 10 EVs in whatever stat they're for, however, the most you can use for one Pokemon and one stat is 10. So if I gave that Tepig 10 Proteins, it would have 100 EVs for Attack. Now you only need to kill 152 Patrats. Still seems like a lot to you? Well then give it a Power Bracer. Items like the Power Bracer, Power Belt, and Power Anklet add 4 EVs of their designated stat no matter what Pokemon you kill (Power items do cut speed in half while they're held though). Say for example the Tepig faints a Pokemon that gives 1 EV point for Defense. If it were holding the Power Bracer, it would get 1 Defense plus 4 Attack EVs. Obviously the better thing to do would be to train it for something that gives it 1 Attack EV plus the 4 from the Power Bracer so you would get 5 each time you killed one. Now you only need 30 Patrats and 2 extra EVs. To fill up those two EVs, you can use items like the Health Wing and Swift Wing. If you've been going around in some of Unova's Bridges, you might've come across some Wings. With the exception of the Pretty Wing, the Wings will give 1 EV for whatever stat they're meant for. So let's get back to Tepig. Say I gave him 10 Proteins and 2 Muscle Wings. It now has 102 EVs in Attack. You only need exactly 150 more, if you gave it the Power Bracer (Find it at the Battle Subway shop), then you would only need to kill 50 Patrats. Lillipup also gives 1 Attack EV so if you want to EV train for Attack, head off to Route 1. But wait! There's another way to speed this up even more! So now with the Power Bracer, every time Tepig kills a Patrat/Lillipup it gets 5 EVs in Attack. But what if you can double it? If you're lucky enough to be able to infect that Tepig with Pokerus, then it would get 10 EVs in Attack! What Pokerus does is it doubles the EV Yield from each Pokemon. Now that your Tepig has Pokerus and a Power Bracer and is killing Patrats/Lillipups, you only need to kill 15 of them to fully EV train that Tepig once you've also given it 10 Proteins and 2 Muscle Wings. Obviously if you didn't give it Pokerus, then you would just need to kill 30 Patrats instead of 15. You can use PP to calculate how many you've killed. For example, everytime I encounter a Patrat/Lillipup for EV Training, I switch it out to my Hydreigon, which has 15 PP in Surf. I can just keep doing this until my Hydreigon's Surf's PP is zero so I know that I've killed 15 Patrats. Remember that this tactic only works for Pokemon that give 1 EV in one stat. This becomes a problem when EV Training for Speed because the only common Speed EV giving Pokemon (Basculin) gives 2 EVs in Speed and that can seriously mess up this calculation. More on that later.

Still with me? Okay. Now you just have to do that for two stats. For the other stat that only gets 4 EVs you can just use 4 wings on it and you're good. Pokemon will still get their full EVs as long as they were in Battle. Even with Experience shares (though you'd rather have it hold a Power Item) and just switching out to let someone else kill the Pokemon. Once you have filled up all 508 useable EVs, you are free to train on whatever you like and give it whatever item you would like. You can even use Rare Candies. Rare Candies are said to do something that messes with EVs so it is recommended that you not use them until after a Pokemon is fully EV trained. There are ways to reset the EVs you have gained but this involves the use of very rare berries which decrease EV's in a certain stat by 10. They're only found in the Dream World and even then they're quite rare.

So now you're probably wondering which Pokemon give how many EVs in which stat? Well as I said before, if you're EV training something for Attack then you just need to head off to Route 1 where you will only fnd Patrats and Lillipups. Both give only 1 EV in Attack so it's all good. For Special Attack you'll want to head off to Celestial Tower, which only has Litwick and Elgyem. Both give only 1 EV in Special Attack. Defense is a bit trickier, the only not-rare Pokemon that gives Defense EVs are Venipede and Sewaddle, which can be found in Pinwheel Forest. Be careful though. There are Pidoves and Petilils there too which might ruin your calculations as they do not give Defense EVs. Special Defense is easy. Just surf in Route 17-18 and you will find Wild Frillishes. They give 1 Special Defense Point. Now HP is also a little more difficult. Common HP givers include Stunfisk, Palpitoad, and Audino, all of which give TWO EVs in HP so they are not ideal for perfect calculation. The only one that gives 1 HP EV is Ducklett, which you can find in those shadow circles at Driftveil Drawbridge. If you're EV Training for HP you can also use this oppurtunity to collect Wings as Wings appear in the shadow circles too. Now Speed is the trickiest. The only common Speed giver is Basculin, which gives 2 Speed EVs. You can handle this in one of two ways. 1) Train the Pokemon for Speed last after you've given it max EVs in the other stats. Then it won't even matter and you can kill all the Basculins you please. Or you can look for Purrloins. Purrloin gives 1 Speed stat. They're not as common and there's no one place you'll always find them. Go to the Dreamyard. Purrloin is most likely to be encountered in the Dreamyard. So head there to EV train for Speed.

So that's EV Training. I know you probably still have lots of questions. Just ask me if you need to clear things up. The biggest thing about getting the hang of this is Trial and Error. Find out what works for you when EV Training and Good luck. For maximum stat growth potential you'll also need to factor in Natures and IVs but those are both completely different stories.

This guide may or may not be eerily similar to Serebii's...