I've had similar stuff happen to me. One trick that has helped to get me out of the rut is to go back to the basics. When I'm stuck I would find a textbook problem, from the very simple (reverse this array, etc) to the more complex (implement a red-black tree). I find these problems help get me back on track and give me useful tools that I might use some day.

I think there are two pieces to being effective at programming. If you have a clear idea of what you are trying to achieve, you can just bang out the code. Unfortunately, most of the time you are understanding the problem while you code it due to very ambiguous specs, so you just can't code as efficiently.

Last, but not least, tweak and tweak away. Write some code, take a walk, come back and take a look at it again. Review your own code thinking about where you are making mistakes, it'll give you a map of what to watch out for.