Hair making tutorials are hard to find. The actual modelling is not hard, and can be done with one of the free 3D modellers - however the mapping and texturing is more critical for a realistic result. The transmap has to be done right, and it helps a great deal if the mapping is very flat, so that straight hairs on the maps appear straight on the final model. You can make half a head of hair and mirror it, but obviously the result would be perfectly symmetrical. Most people's hair isn't symmetrical.