I would add to that. The other day we were in checking some cruise dates, prices and credits. Someone was blaming he other agent for the weather (an Alaskan cruise). It was an early June cruise, they choose the date so they could be back for a wedding. It was booked about 9 months out, yet the TA is at fault!! Go figure.
So #10 would be don't blame the TA for things not in their control.