Being hunting for the knowledge all the time. However, it seems all you have to do is follow your instincts. Obviously I have just started with the crypto after seeing the huge hikes in crypto market. But with my immense experience through Forex and eToro trading I do believe that you have to rely on your knowledge, research on the asset and it's behavioural changes according to the market. It can just give you that "hunch" whether to sell or not!