sell can be known in the market, we can sell when the price is high and improving. this time the market can be used as a benchmark when to sell before the coins back down.
There is no doubt in this thing that you have to sell when the prices are high. Now the question arises, how much this high should be? When you know the market is highest at the peak right now? So for answering these questions, I advise you people to calculate the profit that you want to achieve in one time. this margin profit will help you to see whenever this is achieved, just sell without even getting in worry that have the market reached its highest or not?
I totally agree with you. you have to set own profit margin for each coin. you must trade and invest based on knowledge and experience. Do not based on the trend. do not try to find the peaks, because you never find them. Do not too greedy. If not, you will lose your money.