You should get a Duskull and evolve it [it evolves at lvl 37 to Dusklops] then get a Shuppet the evolve that [it evolves at lvl 37 too] then teach it a ghost type move or dark type move, then train and that is how to beat the 7th gym leader in Pokemon Emerald. Good luck!!
keep using phychic
You have to beat the gym leader, Pryce, in Mahogany City.
Go to Mawille(eletric gym town) and there will be a gym leader... there is no gym leader
You beat Roxanne the first gym leader in Rustbordo City
the 6th gym leader is in fortree city after the weather station where you get castform
Water, dark and grass Pokemon
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.
After you beat leader Norman
get better pokemon
Beat the gym leader
the best way to beat the 7th gym leader is with a fire type Pokemon
you get a dark Pokemon for example mightyena
with fighting type pokemon
You beat Leader Norman, then someone gives you surf.
keep using phychic
in the fortree city
You have to beat the gym leader, Pryce, in Mahogany City.