"The Psychology of the Stock Market" was written by G.C.Sheldon in 1912 and has some insight thoughts on the market...
"The fact is that the more a trader allows his mind to dwell upon his own position in the market the more likely it is that his judgment will become warped so that his mind is blind to those considerations which do not fall in with his preconceived conceived opinion."
"Most of the practical suggestions which can be offered are necessarily of a somewhat negative character. We can point out the errors to be avoided much more successfully than we can lay out a course of positive action."
"But the following summary may be useful to the active trader:"
(1) Your main purpose must be to keep the mind clear and well balanced. Fence, do not act hastily on apparently sensational information; do not trade so heavily as to become anxious; and do not permit yourself to be influenced by your position in the market.
(2) Act on your own judgment, or else act absolutely solutely and entirely on the judgment of another, regardless of your own opinion. "Too many cooks spoil the broth."
(3) When in doubt, keep out of the market. Delays cost less than losses.
(4) Endeavor to catch the trend of sentiment. Even if this should be temporarily against fundamental damental conditions, it is nevertheless unprofitable able to oppose it.
(5) The greatest fault of ninety-nine out of one hundred active traders is being bullish at high prices and bearish"