I don't have good luck with models.

[Claudemir Bonfim]

I think you missed a great opportunity, I had a great time painting a "sleeping beauty". You should have provided her a bed or a couch, sleeping models don't talk, don't take long breaks and don't eat a lot.
I prefer to talk to my models during the sessions, I only don't do it if I have to do speed drawing.
Breaks are important for the models, you have to use a timer to both start and finish a break, when the alarm goes off the model knows he/she must resume the job.
I wish you the best of luck next time.