Avoid bluffing just for the sheer hell of it: unless you are a newbie and you wish to see the result of such

an experimentation. Indeed, I know of so many poker players out there who do will not feel 'macho' enough
if the end of the evening comes without him doing a bluff thing, whether it succeeds or not.
Here is the truth, bluffing only gets to work against particular people and particular scenarios.
Avoid staying in contention for the pot just because you have committed: always bear in mind, you cannot get that pot even if you throw enough cash in there big enough to finance a revolution for a banana republic, if your
cards are pure trash. Cutting one's losses is one hallmark shared by the pros, the gifted and the pragmatic. (I may not be a pro, but two out of THREE ain't bad).
Avoid calling at the conclusion of the hand just to have somebody honest: there are exceptions to this I know, but I am thinking of the generalities. When you think a competitor holds a much stronger hand than yours, he would just jump with joy if you add on to money which is already his, in all likelihood.