After you join the Priority Club Rewards, you will shortly receive few emails about the program and some of them might include a link to a quiz that earns you points. Last year, you could easily get 2000 points for completing number of them as I documented here.
This year, you can still earn 1400 points IF you have not completed these previously.
Survey 1: 300 points
Survey 2. 100 points
Survey 3. 100 points
You can do each survey officially only once. It seems, however, that you can some of them more than that.