Various ways to do it really. Personally, on single targets I just Fester to get the stacks necessary for Trance (sometimes an Energy Drain between two Festers if I'm impatient). With Ruin II and book smacks between. If it's a mob, Bane, Painflare, Painflare.

Once I get into Dreadwyrm Trance I pop Raging Strikes, Tridisaster/Contagion (and if it's on a mob, I'll quickly refresh aetherflow and Bane that), Rouse/Spur/Enkindle. Then Ruin III spam. and of course end with deathflare. ^_^

Of course this all varies depending on the situation, but that's a fairly average opener for me.