I like writing comic pages, discovering the rhythm of the panels, learning how much you can and can't express. It's good to stretch myself as a writer instead of always doing prose work; I write screenplays for the same reason.
Everything you write makes you better. But if you really need a tip, here's one: a good story begins in opposition to its ending. That means you work out how it finishes first, and then begin the story as far away from that point - in terms of character development - as you can.