Go to aquas base in Lilycove
with electric and fire type Pokemon
Go beat the 6th gym leader ^^, that is in Fortree City.
It depends which ones are you looking for. The 8th Badge is in Sootopolis, The 7th badge is in Mossdeep, The 6th Badge is in Fortree, The 5th badge Is your dad in emerald it is found at Petalburg, the 4th Badge is in Fallabore, The 3rd badge is in Mauville, The 2nd badge is in Dewford, The 1st badge is in Rustboro.
at the gym
Go to the Pokemon league.
the ground gym
Destroys picachew
Dewford Town.
You can get the 6th badge by defeating your father in petalburg.
Beat the gym leader
Pokemon league
you travel to lavavine town