Blender features many nice unwrapping methods, of which Unwrap is the best.
1. Open a blendfile with the model you want to edit.
2. Split the screen by right-clicking the border between the buttons window and the 3D window. Choose Split Area.
4. Now you have to place the seams. This is quite difficult to understand, but once you get it, it's easy. It's like skinning an orange, you have to make some seams with a knife so you can wrap off the skin. In the second picture you can see places where seams have to be put. Of course not only there, also on the legs for example. If you want some further theorethics at this, Google it.
5. Select edges you want to become seams, press CTRL + E > Mark Seam.6. Once you have placed all seams, press U > Unwrap. 7. In order of getting good results, you will have to move around the parts of the UV map around, maybe scale them as well. To do so, select a vertice of the part you want to edit by right-clicking it, press CTRL + L. You can move and rotate parts of the UV map just like you can with vertices in the 3D window.