"A series of basic articles aimed at introducing the fundamentals of texturing, covering the various aspects of surface (colour, diffuse, reflection, bump, etc) and giving some advice for getting started as a texturing artist.
A little out of date, but hopefully still somewhat useful."
" What size are you supposed to create your textures? This article will solve this mystery for you! Learn to calculate the correct size for your textures to maximise quality and detail. This article pertains to texturing for film/TV, and not for games.."