It would be making signatures, but I would like to branch off into other things.  Few times recently I tried something other than your standard signature by doing a vertical or using a larger canvas than normal as I did with my Iron Man and Swordswoman signature.  Once I'm comfortable with what I'm capable of when it comes to making signatures I might try doing large art, similar to signatures but would have to put more thought into it with all the empty space to fill on the canvas.