When examining the geology of a region for potential aquifers, what characteristics or factors would you consider?

When examining the geology of a region for potential aquifers, what characteristics or factors would you consider? Also, what areas (based on natural and human factors) would you avoid? Note: don't use any material outside, only use "foundation of earth science" book .Fifth edition, authors: Federick K. Lutgens and Edward J.Tarbuck, if you need cite or reference. You only need write about 200 words. Thank you.