I got hold of this lovely book by Max Gunther. These are basically axioms about investing and risk taking.
First Axiom: On Risk
If you are not worried enough you are not risking enough.
My experience is that whatever you are buying should sound awful. You just need to be the last man standing, if you have some people standing with you then you are taking a big risk.
If you are not worried about your investments then your investment has not bottomed and has lot more to fall.
HE also says everything is speculation and there is no difference between investing and gambling.