ok so ive already been to battle frontier and all so i guess thats the first part of the game.
so each battle is 1 ev. so someone above said 252/252/6 - what does that mean? like the spots - i know the numbers are what i want them to be -well at least the 252's
EDIT: oh and by the way i play emerald
510 is the Maximum number of a Pokémon's total EV's. 252 is the Maximum number of EV'sthat you can get for a Pokémon stat in each category. 6 EV's increases one point.
For example of a 252/252/6, a Special Sweeping Sceptile usually has maxed out(252) Sp. Atk. and Speed, and remaining 6 usually is for HP is just for fillers, it only increases 1 point up in stats anyways, but at close battles, it's very useful.
I'll give you another example to help you understand more. 252/129/129 is usually if you want to boost 3 stats, first the 252 is for the top priority and the 129's are for secondary and tricriary priorties. Like a Annoying Tank like Milotic you want to put 252 at Defense, and 129 each at HP and Sp. Defense. That makes Milotic a living hell to take out along with the right moves.
Hope that helps, if you need more help, PM me.
EDIT: Oh btw each battle isn't nessessarily 1 ev, for example if you beat a Pikachu with a pkmn it gets 2 evs in speed, but a Raichu gives you 3 evs in speed. A Macho Brace attached with a Pkmn gives you DOUBLE the EV's, so if you beat a Raichu with it you get 6 EVs, and so on.
Use the Serebii Pokedex to find out what Pokemons give what EVs.