I don't think that's the answer (s)he was looking for.

Some suggestions:
1) try internet check-in 30 hrs prior to departure to get seat
2) if no luck, try upgrading yourself in the lounge in AMS, if not enough seats they usually send message to gate handler who will do the check.
3) if no luck try speaking to Gate handler yourself, a) for a seat in C on miles, b) for a seat in the rows you want or if all else fails c) an exit row seat, (row 9, 21, 35 on a combi, row 51 also on all passenger plane). But watch out for nasty A and K seats because escape slide is in the way).
And if that doesn't work, good luck, make sure to get an aisle seat and take plenty of walks. And try to chat up the stewardesses, maybe they'll invite you to their overhead crew bunks :-)