How do I do an effect for Darkseid's Omega beams?

You might look into Video Copilot's free Saber plugin. It gives you a nicely detailed beam look that looks great for this sort of thing.

A simple mask path with the stroke effect applied followed by some glow. There's litterally a quadrizillion tutorials for these techniques out there, most often in teh context of "drawing on" some logo.

Mylenium