This is what i usually did when i started newly as a novice trader: I rush into trade not know when to sell out or hold. Lessons i learnt taught me that rushing into trade is always a wrong call. you should always exercise enough patience before entering into trade, and you should be aware of when to stay and how long to stay and when to get out of the trade. and make money
At least don't be greedy in trade. That will make you regret. After you see some profit and you feel enough, just cashout or sell your asset, then if want to start again with same pair, wait it to down again or you can change to other pair.
I think even the old ones here are crypto world are sometimes tend to become greedy.But of course,this should be avoided so you will not end up losing your coins.I also think panic selling is one of the mistakes that newbie traders usually do.They cannot control their emotions watching the price continues to fall and so they do panic selling which make them a loser too in the end.