are you talking about hoenn e4?
you can let your Flygon relearn Dragon Dance in slateport or gym8 city
when you fight steven, use dragon dance 6 times in front of his first poke skarmory
when Flygon's hp down to half, heals 120hp or 200hp first
then use Earthquake to sweep
be careful that claydol's ability is Levitate which is immune to Earthquake, use Feint Attack instead
aggron's ability can be sturdy
you can also use this dancing way to sweep other e4 member too except the ice type elite
always check which poke's ability could be Levitate