Ok short-handed is highly dependend on the opponent when it comes to pre-flop and flop game.
We usually have 4 types (roughly) at the tables. TAGs, LAGs, Rocks and passive fish.
You will need a tracker to indentify then.
Beginning with rocks 14/12 or so.... they are the easiest to play against.. they play very straightforward pocker, raise a very tight range.. c-bet that range almost 100% and will give up turn unimproved. You can call pre-flop with a hand you like IP, float the flop as long as it does not precisly hit him and if he checks turn bet. He will give up a lot of times. You can also avoid that player altogether if you want, he raises so little hands, its like if he is not there. Also if he is in the blinds, just steal from him with a wide range of hands.
Next is the TAG... he is like we are. 24/22 to 18/16 or so. They are somewhat more difficult to play against. Pre-flop you can call them with hands wich have good equity against their range. They will also c-bet a lot, but more selective. They are also capable of second barreling and have a pretty good grasp of the game. Your table image is pretty important here.. they have to respect your game if you want to steal pots from them. I don't advise a float against them anymore since they know what that is and can c/r you on the turn on purpose as defense.
Pre-flop I like calling these guys with suited connectors, any hand which makes my post-flop play easy. I will also start 3-betting them more lightly. The higher their pre-flop raise percentage is the wider your 3-bet can be. They will respect the 3-bet because they don't like playing OOP vs another TAG in 3-bet pots.
Flop I will float them with top pair for pot-control. They are agressive, why raise if they might second barrel whatever they have? You can decide on the turn or river if your hand is good enough for show-down vs them.
K then we have have LAG, ca. 35/30 or so. He is unpredictable with starting hands so I won't get into it. He raises like low suited connectores in UTG etc. So what do we do? We 3-bet him with like almost every hand we want to play against him IP. OOP we rather fold unless we got something really strong to 3-bet. LAGs want to see a lot of cheap flops, they hate 3-bet pots where they are OOP... and their game changes. All of a sudden their aggression goes away and they become passive or super straight forward.
Don't ever just call IP vs a LAG... he will crush your TP with some kind of weird 2-pair or so post-flop if your all-in. You cannot trap him because he seems like a maniac.. good LAGs have very controlled aggression since they know what you hold.
Oh and if a LAG c/r you post-flop he most likely has you crushed somehow, unless you really hold the nuts.. but something like AA, KK or TPTK is probably crushed.
Because of LAG style you want to avoid being OP vs them.. they call with just too many hands. But they are capable of folding a lot of their hands when you place good c-bets on suitable boards and the occasional second barrel or c/r to their floats.
Last is the fish... 40+VPIP and 10-PFR. These guys just call.. check... call etc.
Just play for value. Don't ever bluff... dont ever get mad (they will chase gutshots like if its the nuts!!! dont ask me why).. if there is a draw... and they c/c you all the way and the draw completes just check behind.
Oh they will donk bet into you occasionally... to "test" your hand with like half sized bets or something, because they somewhere read some strategy about semi-bluffs or something (don't ask)... just raise it even if you don't really have anything for showdown on the flop. They will fold more often then not. If they call well your up against any sort of pair or draw, they will almost 100% check the turn... you can try to take it away now by placing a standard bet. If they bet again however they do have something, if you have TP just call now if the bet is not to precise and re-evaluate the river.
K lastly.. for all of your decisions be very aware where these players are at your table. Like you cannot float call a rock, or isolate limpers having a weaker range with maniacs and LAGs behind you. You also have to be aware who is in the blinds.. if you have a TAG in the BB and you a rock or a TAG raise UTG and you want to call with like 89s, BB might squeeze.
You can also use other things to your advantage... like is a TAG isolating a fish form the BU? If so his range is weak and you can 3-bet lighter from the BB taking it down a lot of times. Or are you 3-betting LAG raises too much, LAG might react and start calling more.
Just keep everything balanced and always be aware of you position, table image and who else is playing. Oh and keep a watch out for stack sizes... we sometimes start stealing automatically while multitabling not seing the shorty in the BB.. sucks if he pushes etc.
This is also important when adjusting to LAGs etc... if its like a half stacked LAG or short maniac we goto ignore him until we can put him all-in pre. 3-bets vs him just commit him so tighten up you range again.
Just go play for a while and enjoy the game. Not sure what stakes you play but every limit has different betting patterns people use to try to gain value from their monsters. You just goto spot them. Most players where we play are fish... LAG are also a form of fish at these stakes since I don't believe they really know what they are doing yet and how we can exploit them. Just watch out for regs who have TAG stats. You will normally devide the entire table between you two and take them all out clashes between you two are minimal. Leave the table when you get like 3 TAGs... its just not profitable unless they got some big leaks or you want to work on your game vs them.
Cheers, hope this helps. Just what I picked up over the time I played.