For business travel, schedule convenience for the trip's purpose comes first (obviously), then price (by company policy).

Schedule convenience includes minimizing connections, since each connection adds significant amounts of travel time, and increases the chance of problem (like missed connection due to first segment arriving late). It also includes flying to/from airports most convenient to the origin and destination.

Minor factors will break ties when schedule convenience and price are reasonably close. These include frequent flyer programs, in-flight amenities like personal TVs, and seating choice (as a non-elite passenger, Southwest is better than most airlines, since the late booking business traveler on an assigned seat airline tends to get the worst seat -- elite frequent flyers will naturally prefer the airline that they are elite on, because they will get the best seats even if they book late).