Our mind is wired that when everything is going up we want to invest expecting the price to keep rising and when it goes down we want to sell because we fear to be locked in that price for a while or in the worst case lose too much. But how Warren Buffed once said: Rule number 1 is to not lose money, and rule number 2 is to not forget rule number 1.
The sense behind that sentence is that before investing, you have to analyze the coin not only using the actual price and price action but also its fundamentals. Check the coin website and see if their coin has utility in their system. Also, check if the coin generates any revenue or has a strong utility. If the project has potential, no matter if you buy too high, because over time the price will go eventually back to it's all time high if the fundamentals are strong. This give you security that no matter how low the price will go, you still can sell with a profit if you have enough patience to wait better prices.
