I'll be the first to tell you that I flunked woodworking in grade school. Because of that, I've resisted the idea that I could build a simple birdhouse, thinking it would look more like an ashtray. As it turned out, even I could construct a decent looking birdhouse. You can find plans for building birdhouses on the internet. One place I found useful is 50birds.com. They have free birdhouse plans for all types of birds. Also, one book I have found to be very informative is the Stokes Birdhouse Book by Donald and Lillian Stokes. The pictures below show the construction of birdhouse #2. The dimensions below are for wrens.