I guess the best advice I received so far is to always make sure that my emotions are settled before I make a move in the investment.

As for the worst, I remember when I was a novice, I joined this forum and asked for some tips. One of the members told me that stop loss is not necessary because I might miss the sudden change in direction where I could have profited instead. Some disagreed with him but many also agreed. I did that but only bad results came up.