i play tight when im a big table, but when it comes to heads up i switch gears and play aggressive.
-Usually during heads up play, the hands dealt are live cards, so even with a mediocre hand its good to see the flop if its cheap.
-even though its live cards, you really dont want to spend to much to see a flop with a small hand. In HU, high cards are usually dominating preflop
-Flopping middle pair in HU is good, flopping top pair is even better
-Raise big with A or K high and steal the pot with those high cards
-Raise big with Q or J and steal pots, but i wouldnt put as much trust in a Q high then i would with a K high or better
-Try and avoid bluffing
alot in HU, its very easy for your opponent to have hit anything on the board. Unless i have some draws showing...ie: overcards, straight, flush, i would refrain from bluffing at a hand.
-In SB i like to raise a lot with decent hands 10 - A high card. i rarely just call in SB and im usually folding anything thats a 4-2 low card.
-In BB i raise a lot with face high cards and just call small raises in decent hands.