I suggest reading this first tutorial before the second if your completely new to texture creation:
http://www.onona3d.com/pdf/texturing.pdf
http://www.onona3d.com/pdf/PhotoshopTips.pdf
The second one covers correct use of the stamp tool, and accurately making seamless repeating materials
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And if you need a good guide for modeling a face (Good face modeling tutorials are rare) Here is a great one using the polygon extrusion technique:
http://www.3dcm.com/facemodeling/tutorialfacemodelingIndex.html
Hope you find them helpful
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And dont be lazy, read all pages GOD Damnit!