10 common mistakes made in investing

1. Investing in money which you cannot afford to lose
2. Investing when you do not have holding power
3. Investing without the necessary knowledge
4. Investing emotionally
5. Wanting to win all the time, but will not admit to mistake made
6. Falling in love with your investment
7. Gambling rather than investing
8. Investing based on what has just happened.
9. Trying to time the market, thinking that there's a "best time" to invest
10. Investing beyond your risk tolerance

From the book "What your school never teach"