This is my experience and it suits my style of play (and usually the people I play with), so take it as it is.
a) I value position a lot more, especially if I get limpers who usually play "right" preflop and don't try to slowplay too much. KQs suddenly becomes a monster in these situations.
b) I get more agressive with my hands post flop: with probably many hands going HU, the chances of your opponent catching the flop diminishes greatly. I try to take down many small pots.
c) Ace/rag (A8s, A6s, etc.) gets more valuable and warrants raising. I am careful about not getting picked on for doing so: being aware of what the other players might have if they reraise you is primordial.
d) I'll play ATC more often from middle/late-position, especially if somebody minraises sweetening the pot.
e) Middle to low suited connectors gain in value if the betting is fierce preflop (and youi have a big stack) as you can generally assume they are still live on the flop. The trick is to play them for their straight and or flush possibilities, pairing them still doesn't indicate a big hand unless HU against someone who has overcards.
f) Switch gears more often as people will have more info on what/how you play since you enter more pots.
g) Pocket pairs, even small ones, become more valuable and should be raised, especially if you raise lesser holdings on a regular basis.
In conclusion, I try to see more flops. This, in turn, means not so much that my hand selection changes, but my hand selection vs position gets more and more agressive. I won't usually play J10 under the gun, but with nobody raising, they are like aces once on the button.
I firmly believe that UTG play shouldn't change a lot (sure, hands like KQs go up in value, but will be mucked if I don't have the right flop or sense that I'm getting dominated preflop), but that when you have position, almost ATC can and should be played hard. Lossening up like this needs a pretty tight table or a table with wich you're familiar. On a strange or very loose/passive (one that can't fold for example), bluffing
might be unprofitable and I'll play tighter.