Jonas Hummelstrand has an excellent resource on his site:
http://generalspecialist.com/greenscreen-and-bluescreen-checklist/
That resource and some other good ones are linked to from the “Shooting and acquiring footage for keying” section of After Effects Help:
http://adobe.ly/RNe3pz
Can anybody suggest a link that has the most authoritative, comprehensive tip sheet for green screen shooting that I can send to this particular client the next time they consider doing it?