the only solution I can think of is forgetting about online check-in/Amadeus or Galileo at travel agents and just turning up at the check-in desk as early as possible to ensure they allocate you the seat you want
Doesn't always work either
eidah. Most of the seats have been taken up either through online check-in, or when checking in on the preceeding connecting flight, or on the outbound leg of a 24 hour return (when you can check-in for your return).