> After landing we discovered that checking in at the right time might get us further ahead in the line but we tried that, checking in within minutes of checkin

> After landing we discovered that checking in at the right time might get us further ahead in the line but we tried that, checking in within minutes of checkin opening and were still pretty far back in the lines. "Minutes" isn't good enough. I travel Southwest with my wife all the time and we have never failed to get seats next to each other. You need to go the the check-in form 24 hours and 2-3 minutes before your flight, have your confirmation number and other info filled out and click "Check-in" the exact second the clock turns over to 24 hours before your flight. That will probably get you a low-numbered B or a high-numbered A boarding group.