K, I took Deme's advice and now mix up my shortstacking and deepstacking. I usually play 30-50 hands short and get an idea about the table and the players then usually top up to the max buy-in and play deep. So far it is working good.
Now that you have some reads you can play the players. One of the most common mistakes I have noticed is players min-reraising when they have AA or KK, deeped stacked this is awful since you get no implied odds on a safe flop and the better opponents will pick up on it.
Example:
This afternoon playing .5/1 NL on Betfred, 10 player game
Hero is on the CO andhad 300$ in chips (doubled up off a few idiots already

)
The button had about 80$
The BB had 65$
Hero is dealt
Folded to hero who decides to raise to 4$ total, button calls, BB raises to 7$ total (min raise), hero and button call.
Flop (21.50$ pot)
BB bets out 20$, Hero raises it to 60 total, button folds, BB calls and goes all in.
Turn and river were blanks
BB berates the hero for being a fish, hero explains he is new to poker and explains how he has a hard time folding suited cards.
Anyway I was just pointing out how stupid min-reraises are with big hands, I got lucky hitting the flop but I had major implied outs for hitting my flush, straight, trips or 2-pair. If you are going to raise-RAISE.