1) assuming it is easy to make money
2) no plan for each trade
3) having the wrong habits
4) emotionally tied to a stock
5) not taking profits into strength
6) holding on to losers stocks
7) averaging down incorrectly
8) using excessive leverage
9) trying to save a losing position
10) following people blindly
11) looking at the short term
12) not investing in yourself
https://klse.i3investor.com/blogs/khgoh/2017-08-16-story-h1451406690-12_common_mistakes_beginners_make_in_stock_trading.jsp