I once read about two brothers who wrote and illustrated fantasy books. They'd make costumes and then "persuade" friends and family members to dress up and pose for photographs which then became references for their paintings. I've drawn quite a few different people who I sort of envisaged as interesting character types but never one who really looked as if they stepped right out of a fantasy novel.
The model for our first portrait class of 2011 had not cut his hair for 25 years. He arrived in bare feet with a wealth of interesting tales about his life. He is known to young children as "Gandalf" and he really seemed to have the whole wizard vibe down pat. This last sketch of the day took 15 minutes and was in graphite on white paper, perhaps a little less as I stopped before adding too many unnecessary details to complicate the drawing.
I took plenty of photos from different vantage points so if I ever need to write and illustrate my own wizard story I have a ready made muse to work from. Till then this particular image of a Kiwi Gandalf is stuck up on the fridge.