Adjusting UVs

You can, of course, adjust vertices on the UVs to make sure they look right in the 3D model, and you’ll see real-time feedback in the UV Test Grid of the 3D model as you make those adjustments.

Remember, you also have Proportional Editing tools to move groups of vertices subtly, and you can also move, rotate, and scale them. Try to adjust the grid for the face so you have smaller squares in the face than in the back of the head; this will help you optimize the texture size and have more detail in the face, which is where you need it, instead of the back of the head where you don’t need it.

You also have alignment tools for the UVs. Look at the options on the UVs menu on the header and try them out—maybe you’ll find something interesting (press W to get the Align and Weld options). Also, when you use a tool, you may need to make an adjustment to its effect before you confirm it: in those cases, the header will show information with instructions you need to follow to use that specific tool as well as its current parameters, so keep an eye on that header!

Something else to note is that you can use the Snap tools as well, which are very useful when, for example, you want to align one vertex on top of another.