What I did to tame my Bobs was to go to the equestrian store and purchase a small bit. Acme makes an excellent halter and bit for quail. Once the halter is placed, I lead them around the pen. This also forces them to exercise, which prevents muscle atrophy.
I suppose the best way to tame any animal is to handle them allot from birth and get them use to your presence and bribe them with treats. I don't know anything about quails specifically though.