First, buy. You have to judge under what circumstances and how much to buy. If the market does not develop as you want, what should you do with your position? If the market develops as you want, what should you do? 1, buy in a simple uptrend. 2. In the callback of complex uptrend, buy when there is downward fractal. 3. Buy when you break through the previous high. 4. Buy at the lower edge of the sideways trend pause. These four principles are the basic principles of purchase transactions. When one of these four situations does not appear in the market, try not to consider buying. Second, sell. Many times there will be some "feelings" about market changes, and these "feelings" should be based on your trading system. When the market develops according to your system, you don't need to do anything but observe patiently. You have to understand that as far as trading behavior is concerned, it is an instant thing. There are more than 200 trading days in a year, and the real trading may only take a few hours. Others are long and lonely waiting.