it's pretty fun and effective as a mixed attacker:
Flygon @ Life Orb
Rash Nature (+Sp Atk, -Sp Def)
196 SP ATK/104 ATK/208 SPD
-Draco Meteor
-Flamethrower/Fire Blast
-Earthquake
-U-Turn
the key of this moveset here is causing good damage with Draco Meteor to whatever switches in. you'd obviously bring Flygon in against Skarmory or something else either weak against Earthquake or Flamethrower/Fire Blast, and of course, they'd switch out to something that resists it, or absorbs it. you'd then surprise them by using Draco Meteor, which would do serious damage to anything that isn't a sp wall and resists it. then, if you're faster than the switch-in, you use U-turn.
you can also use U-turn if you already know what your opponent has. if you have a feeling that they will switch in something that is weak to U-turn but has supereffective attacks against you and may be faster than flygon, like Starmie and Weavile, then use U-turn on the opponent's switch.