I use alot of cross hatching. It works pretty well for me. To reinforce what others have said I think the most important things you need to do are to have a unique inking style and great page layouts. Im gettin Manga Studio soon... So Ill get to start experimenting with screen tone! Im FN stoked!!!!!

lay of and go easy on the toning, make the enviroment more grayis and thicker lines around the characters, so they dont get absorbed by every thing else. And go easy on teh shadows on characters.

This little trick doesn't involve some technical thing you have to do with your comic, but it's something that I think has made my comics a bit more appealing.

Make a new layer on top of the other layers you have for your page, fill it with a solid color (preferably a dark one), set the layer properties to "screen". Of course, I don't know whether or not you want to keep your comic strictly B&W, but if not you might find this worth trying out.