it really depends how far you are in the game... usually trainer battles level them up fast but if your trying to level up a low level Pokemon after you already completed the Pokemon league you can level it up to about 16 in the victory road by sending it out, then immediately switching it for a higher level Pokemon.
Also, you can send any Pokemon to the day care...once you do this, find a heavy object to place on your move buttons....get an acro bike and go to any slope that you need a mach bike for....start going up the hill, but you can't because of your acro bike...place the heavy object on the pad (up) so it keeps trying to climb the hill...every step is 1 XP point for Pokemon in day care....leave your game boy like this for an hour or two and your Pokemon will be leveled up quickly (my level 51 sceptile went up about 10 levels to 61 in an hour or so)
i think it also depends if you want to take you time or not. if you don't do what they said above.the stats will just be lower. but if you want a Pokemon with a high atttack or other stat just ev train at one of the spots below:
attack: shuppets or mightyenas by lilycove in the level 30s
defense:team magma hideout has all defence iv giving Pokemon level 30s
Sp Attack: spindas by fallarbor only level 15
Sp Defence: i heard that artisan cave has just smeargles to train on not sure though
Speed: Any zubats or golbats you find just not the ones on victory road or it wont be as high
Also some items help them get more so you don't have to waste you time like a macho brace a exp. share or if your lucky enough to get pokerus. if you don't have it don't try getting it youll waste even more time finding it. I know it works because my absol is only lv. 40 but has about 200 att for its stat. But if you think it takes too long just do it the fast way.
In route 1 thas the best way to train pokemon if your pokemon lvl `10
elite four again and again.worked for me
the only way to evolve it is to have the feebas at a high BEAUTY status for Pokemon contests. and the best way to do this is to have a feebas with a MODEST nature.
It's pretty obvious... EV train (I suggest EV Training in Defense)...
Go above Odale Town when you first get your starter and train it there until it evolves and then challenge your rival.
In route 1 thas the best way to train pokemon if your pokemon lvl `10
The best way to evolve a Pokemon is to train them often. If they have evolved to their last state then they can't evolve anymore.
To beat May, the best thing to get is a Roselia and train it really high. It learns Mega Drain @ lv.17
elite four again and again.worked for me
the best way to train your Pokemon is to use a cheat code for super exp gain.if you don't have a action replay you can find them at walmart. the cheat is already in the AR.
the only way to evolve it is to have the feebas at a high BEAUTY status for Pokemon contests. and the best way to do this is to have a feebas with a MODEST nature.
not in ruby or sapphire
Give the Pokemon a soove bell and train it such as if its level 5 train it against Pokemon level 2,3, and 4
It's pretty obvious... EV train (I suggest EV Training in Defense)...
Train it.
Take them to the elite 4 and battle there.
you can not obtain the unown anywhere in the wild in Pokemon Sapphire. the only way is to trade it from Firered or Leafgreen