Differences/Adjustments in NL Heads Up games?

Hey all, I sometimes mix in $10 or $20 NL HeadsUp SNG's and shootouts on stars for fun, and have been fairly successful at them. However, I was recently playing a 100e ring table on martins, and everybody but me and some other guy left. (it basically devolved into a pissing match) At first I took him for his entire buyin, but he rebought and proceeded to take it back, and then some.

I was just wondering, how should I adjust my play in these different heads up situations? (Your input, or links to info would be great)
1) At the end of an MTT
2) At the end of a 1-table sng
3) headsup sng
4) heads up in a cash game.

Thanks!

read the faq?