Research the school thoroughly. Speak to people who work there.

I had a friend, also a single female, who worked as a teacher at a school here. She was lied to from the outset, had horrible accomodation and was basically treated not much better than a third-world labourer.

But Doha on the whole is an okay place to live. Plenty to do if you do want to go out but it's bloody expensive for a decent night out here. It's a good base for exploring other countries in the region as well.