When I start out with a sketch, I can easily extrude it. But after its extruded, I can't just click on one of the new faces and extrude that unless I sketch that face first. If it happens to be a simple rectangle its not so bad, but if it has alot of edges on it, it becomes time consuming. Coming from 123D it seems like there must be a quicker way of doing this. In that program I can click on any face and extrude it. Am I missing something?