So I know this is a stupid question, but since I first started playing pokemon as a kid in 98, I've always just overleveled my starter and torn through all opposition with him alone.
Then XY/ORAS came out and had full party exp share and I started raising full teams and loving it, to the point that I dont want to play the older games because I'll miss having a full team of useful mons.
So my question is this: how do you effectively level an entire team in the older gens? Is it just mass slaughtering of wild mons or is there something I'm missing?
On not-so serious battles (not gym leaders/e4/champ) I start my team with whoever requires the most exp to evolve, and switch to whoever needs the most after the original gained exp.
If your pokemon are of around an equal level: rotate them around regularly in battles.
If you have a pokemon that's of a significantly lower level, grind it up a bit on wild encounters until it's caught up or nearly caught up.
If you have a pokemon that's of a significantly higher level, refrain from using it until the rest of your party catches up.
>Catch a Pokemon
>Put it in the first slot of the team
>If you can defeat an opponent, do so
>If you cannot defeat an oppent, switch to a stronger Pokemon
Alternatively, just give an Exp-Share to the Pokemon you want to train until it can defend itself.