It is very difficult to predict the right time to sell your tokens. I believe this the main problem so as most often the price is rising artificially.
Hey while its true that no one can predict what is the best time to sell, I feel one should not be greedy and sell alts the first chance he gets. Ill tell my story I have two alts Bitcoins Cash and Deep Onion, the former hit $3k plus, and the latter hit $20 but I was greedy and I didnt sell them and today theyre literally worthless. Hence in my personal opinion youll should sell it immediately you get profits, and not be greedy.