I'm currently having a lot of trouble on finding a stellar strategy on using a Flame Body Volcarona. I've been thinking of running Quiver Dance, then a Fiery Dance to raise the Special Attack even more. If you think this is good, then tell me. If not, please put another strategy as an answer.
Quiver Dance is a solid idea, its kind of what Volcorona is known for in the competitive scene. With already high special attack and a +1 boost, Fiery dance may not be worth having. It may have a chance to raise the SATK but it also has low base power and may not be enough to initially kill an opposing Pokemon which would then prevent you from sweeping (you're screwed if you don't get the boost also). I personally prefer Fire Blast for the power. Though that just comes down to personal preference.
What you may want to try is a bulky set in which you invest in both HP and Def allowing you to take all kind of hits. This will allow you to set up more Quiver Dances in the long run. Roost can be used to regain health and Giga Drain will be good service in dealing with Water types hitting them both super effectively and regaining HP. HP investment paired with the high SDef and SDef boosts (Quiver Dance) will allow you to take on and set up on weak water type Pokemon that are special based.