Using a Sableye is quite effective as physcic moves don't effect it and that it can use dark and ghost moves. A Sableye level 50 (train harshly in the begining so its easier after wards.) that knows Shadow Ball or Theif is good as you could earn items. Also any water Type Pokemon that can learn surf would be nessecary to beat the gym leaders. Stock up on Hyper potions and super potions and full heals.
You go to Sky Pillar after the 7th gym in Emerald. There are only 8 gyms.
the 7th gym is in mossdeep city
Defeat all of the Gym leaders on Emerald. ~KKMG1
The seventh gym badge in Emerald is located in Mossdeep City.
get a pokemon, then you train it, get it really strong, and beat th ecrap out of all the 7th leader's pokemon. Its easy.
Go in. Beat the GYM. THAT SIMPLE
beat the 8th gym
mossdeep
In 7th gym
after you beat your father's gym
beat the 8th gym
the best way to beat the 7th gym leader is with a fire type Pokemon