If there are no good ($0) seats left during seat selection proceed without selecting a seat. There’s a good chance all the crap middle seats will get selected by others and you’ll end up getting a seat they were trying to charge $30 for.
Sitting in an airport right now.. Bring gifts for your flight stewards. A small bag of chocolates does wonders for your experience.
Things I have recieved: So much free booze. Free food/snacks. Seat upgrades. A personal thank you over the P.A. Free hotel room voucher, food voucher, transportation voucher.
Tldr: Bribe the help.
If you frequently fly in the US, getting TSA pre-check is phenomenal. I live about an hour and a half from the nearest international airport and fly quite frequently, sometimes when the airport lines are absurd. After having TSA pre for two years, I don’t think I could ever go back.