Personally I don't plan my teams much. I have a vast variety of Pokémon which I use in battles (around 60 right now). I just put them randomly together, just making sure the weaknesses are somewhat covered.
I find nothing more boring then planning ahead all attacks of the Pokémon so they match and assist each other and form a team of out of them. You always end up seeing more or less the same Pokémon in battles that way.
I even made a team out of six Fire Pokémon once and won as many times as I've lost in online battles.