Pokemon EV Training, IV Training and Pokemon Natures

What is EV Training?
EV training is pretty complicated but I'll try to put it in the simplest of words. Basically, EV training is beating specific pokemon to gain "Effort Values". Every four EVs you obtain in a specific stat (ex. getting four Attack EVs) raises the stat by one permanently. In other words, just kill the pokemon in a stat area with the pokemon you are EV training.