Since you're not flexible enough with dates/destinations, etc to fully utilize a FF program (although you should still make sure you're earning miles for all of your paid flights anyway), consider getting a credit card that gives you points instead of miles, and then lets you use those points to purchase airfare. Chase Sapphire Preferred is a good card for this ($95 / year annual fee), Venture One Capital ($85 / year, I think), etc. I think with both of those cards, you also get a little bonus when you redeem the points for airfare.