I intend to create an RSS Reader as a start. Most of such projects will be self-productivity apps. But, when I am convinced I'm ready to create full-fledged apps, I will move on to create a game (for a start) that I had in my mind since years.

To be honest, at the moment, I'm not really into earning an income from creating apps for WP. I just do it for the fun, maybe even earn if possible. When I actually reach to a point, when my skill becomes professional enough. I would want to look for opportunities related to my current activity.