HU and 3-handed strategy info?

I was at a 6-max table with 2 huge fish, 4 handed initially. Dropped to 3 handed, then 2, then back to 3, but basically me and fish. I've seen these guys before 6-handed and a VPIP of 50-70 wasn't uncommon for them 6-handed.

I got crushed. The fishes LAGness was ideally suited to short handed and my game wasn't. I simply don't know what to do in such short handed games. Is J7o on the button a raising hand 3-handed? Does a 3-bet from the BB really mean much, should I call down A-high after that? Partly I was ran cold on cards, rarely seeing face cards, but I compounded it badly by not knowing how to play the hands I did get.

Every Ace-high and small pair I saw showdown with would lose, every good hand I couldn't get action. I was stressing every hand trying not to fold weaker, but good hands like AJ that missed, yet I found I was missing value bets right and left one things like having pocket 5's. I'd hit bottom pair with 97o and have no clue what to do.

Is there anything other than tons of play to help get the hang of such short handed play? Concepts like outs and raising for value seemed to go out the window as the pot size was almost never big enough to chase and there were never enough players to raise a drawing hand for value.