Take heed of the wize one - aka Acadia.
One of the thigs that I looked forward to before I got Poser was making my own hair in the Hair Room. It didn't take long before I realise it was just beyond me.
Also note, again mentioned recently by Acadia, that any hair can easily be made to fit any character.(without any hair fits).
The Pose, Material and Cloth Rooms are the only useful rooms IMO.