The first thing, always take different kinds of pokemons with you. A GOOD ADVICE, never take electric type or grass types with you. If you pick venusaur, then i'll advice that you DO NOT take it. the best team is
Charizard,Rhydon,Lapras,(Articuno, Zapdos or Moltres), Kadabra and Snorlax.Remember, Snorlax is a very strong pokemon and is found in a good level(lvl.30)You can replace Rhydon with Muk. In the legendary birds, I advice Zapdos, because you have a fire type already and Articuno is comparitively weak.You can replace Kadabra with Pidgeot, which I advise you do. Dragonite is hard to train, but if you have the time, it is the best. ALWAYS REMEMBER, never replace Charizard or Lapras. The first league challenger, the ice lady is the most dangerous(I experienced) so you can send out lapras at the end and(Because it is not affective to the attacks) you can cure your fainted pokemon.