What 6 pokemon shoud you use in pokemon emerald?
whatever suits you, everybody has their own style, lots of people have different types of legendary pokemon and switch off when that type is needed(ie: you have lugia out then switch to raiakou cuz the enemy is about to use swampert) or each of your pokemon has a move to destroy their weakness, or a normal type with a viraiaty of attacks to take on any foe.