Going beyond rules of thumb
While studying chess master games years ago, I noticed that those masters would often think very independently, ignoring all kind of "rules of thumb".
I remember one game from GM Ljubojevic where he had pushed several pawns on the white kingside, and then played ... 0-0 !? and continued to win. Wow... I was impressed !
It was something like this :
I also came across chess games from masters where one master would voluntarily go into a very dangerous looking pin, but had calculated and seen all very well, and continued to win ! Amazing !
And that, being aware of exceptions, is something that beginning chess players need to learn.
Apply rules of thumb, but learn to evaluate chess positions and find the exceptions, and also avoid "seeing ghosts".
If you don't play certain moves because you're worried about something, but refuse to calculate and then see everything clearly, then you might be missing some opportunities.
Here's a fresh example :
A chess friend of mine doesn't like to have doubled pawns, and grabs every opportunity to give the opponent doubled pawns.
However, things are not so black and white though.
Doubled pawns can be very very handy in certain positions.
It is just a matter of evaluating the remaining positions afterwards.
Let's have a look :