Content is a real problem. The best solution is to hire artists/musicians. It isn't so expensive. Actually a good game with professional art will return the investments and more.

Another problem is self-motivation. Personally I'm full of enthusiasm at the start of a project and have to force myself to finish it because I want to start another.
Solution - good games in development. Really interesting and challenging (both in play and development) game can be a source of motivation.
Unfortunately, most of casual genres are too simple.