Always...Always...Always...Be nice to your gate agent. Also dress the part, you not very likely to get upgraded if you don't look like you belong in F in the first place. Biz-Casual is perfect. Ask if there are any other available seat, EG:Bulkhead or exit row. Don't make up sob stories about being sick or something. Also be flexible if an oppurtunity to get bumped comes along, ask to be seated in F on the next segment. I don't fly nearly as often as others on FT(Maybe about 6 times a year) but I have been op-upped to F twice, and given an exit row or bulkhead seat almost every other time. It pays to be nice when traveling.