If booking very far out, I try and book the cheapest and shortest time connection possible since the possibility of a schedule change allows for flexibility - opportunity to change to different times later, force rebooking on to more heavily booked/lucrative mileage routing flights after a sked change, or turn a nonrefundable ticket into a refundable one.

Above strategy is even more lucrative on DL but still decent advice for AA.

If booking close-in on a trip I know I will be taking, I shoot for intermediate connnection times: say 1-2 hours (for D>D or D>I, longer for I>D). Long enough to allow for a minor delay and Admirals Club visit while still being able to board early for overhead space.