How to Choose an Airline Credit Card

I need experts who are specifically knowledgeable about rewards/travel credit cards to discuss the criteria for choosing a card that is focused on earning airline miles. These will include: What’s your flight style? How often do you fly, where do you go, do you travel with family/for business/etc.? Do you spend a lot of time in airport lounges? Airline loyalty — do you tend to stick with one airline? Would you prefer flexibility? What is earning and redemption like?