I know when to sell my altcoins when it reaches the price that I expected. I don’t expect too much cause greediness is bad. Sometimes, you want more profit and end up to loss. Because of this, you need to wait again for your coins to go up. Also, I am not in a hurry when selling my coins even I know that I get profit on it. I’ve well-research the coin and interact with the community what will happen next. It’s very important to interact with the community of the coins you invested.