Forum talk:Neekerivittu/@comment-6327130-20130205182710/@comment-3238314-20130205204253

While the mark is active, you should deal damage with everything you have. skills, items, auto attacks. Auto attacking is actually quite important, since your E doesn't cancel the attack animation.

It's also recommended for you to learn about how much damage your ultimate will deal, such that you can change the target you're focusing when the marked target is certainly going to die.