EV Training Done Easily!

To start off ev training, you have to decide what pokemon you want to ev train and in what stats. If you have pokerus, don't spread to the pokemon yet until you're sure it can attack and defeat the pokemon on its own.

wild pokemon => 1-2 evs
power items => 4 evs
pokerus => x2 of total evs per battle

For example:
Lets say i'm ev training a infernape on attack and speed and giving the infernape a ev spread of 252 evs in attack and speed and the remainding 6 evs in hp.
Since seakings and gyrados give 2 evs each in attack and infernape is given pokerus and a power bracer, the amount to defeat the seakings and gyrados are calculated like this:
2+4=6
6x2=12
252/12=21
so in total, i'll have to defeat 21 seakings and gyrados. So how are we gonna do 6 evs for hp? Since bidoof only give 1 ev in hp, the amount to defeat the bidoofs are calculated like this:
1+0=1
1x2=2
6/2=3
so, i'll have to defeat 3 bidoofs to get 6 evs in hp.

EVs help
HP
http://www.serebii.net/pokedex-dp/hp.shtml

Attack
http://www.serebii.net/pokedex-dp/attack.shtml

Defense
http://www.serebii.net/pokedex-dp/defense.shtml

Special Attack
http://www.serebii.net/pokedex-dp/sattack.shtml

Special Defense
http://www.serebii.net/pokedex-dp/sdefense.shtml

Speed
http://www.serebii.net/pokedex-dp/speed.shtml

If you have any questions about ev training, feel free to pm Scep.