I like this thread, hope im not too late.

In used to do the same thing. either worry about loosing my stack & usually end up loosing it.

One of the biggest things to recognize is the dynamics of the table.

As mentioned you have to watch for the changing players and for me it was to shift my style of play depending on how long I was at the table before my run or big pot. You have to expect the players around you to "tag" you as 'tight', 'loose', 'maniac' etc.

My biggest mistakes was not ajusting to the table as the table adjusted to me.

A perfect example was over the weekend I sat at a $50 nl table.
Table was tight as hell so I upped the agression and was stealing pots like crazy. Then I got caught in a couple of showdowns with marginal hands and I started getting called and reraised alot.

WARNING.

I the past I would have kept pumping it up. That session I slowed it down, tightened it up and before the table caught on I caught KK and raised.
Got called and reraised and ended up stacking a guy to double up. He was still thinking about the first hour of the session when I was agro.

I still laugh at the times when a player changes and I don't notice it.
The first guys was tight as hell and you have been stealing on him all day. He raises and you reraise him and BAM he comes over the top.
WTF you think and then notice his name. OOPs wrong guy!!!