most mistakes of traders are;
* Having no proper training in the craft to attain knowledge about it.
* Having no experience traders that is good in the craft to guide them.
Not everyone has an access to this so in a way it's not really a mistake on the newbie trader side, some people just started trading and they just gained their own experience through continuous losses and gains and even if they try and find a school that does this exact thing, they're going to get nothing out of that because the market is volatile and they might not even use a lot of the stuff that they've learned in that school when the actual trading happens, mentors are expensive especially if you don't have a connection.
Trading is one thing that you cannot learn from institutions like schools and colleges, you have to try yourself and take risks to learn it. Otherwise you cannot learn trading. The most important thing while trading is to trade patiently without panicking. Because no one can tell when a coin will be pumped or dumped. Because of this one thing that one has to keep in mind when one goes to trade is that one has to be patient until the profit is made. If you panic and sell crypto, you will lose