How to overcome the fear of holding?
For me the best thing to do to overcome the fear of holding or investing is you need to set the goal before you use or sell that token lest say you want to cashout that investment for your retirement fund so no need to see if the market goes up or down because you focus on your future. But make sure your investment can bring you a profit in the future.
Targets are made so that you are not confused when to sell your coins, but for fear I think it will be about trust? if someone is trust of their assets or coins they have bought, then even the price of that coin will weaken he will be confident with the potential of that coin, so I think you should buy a trusted and potential coin first, before believing to hold the coin
However, you have to remember you do not know which cryptocurrency is potential and trusted cryptocurrency.
There are many scam coins, not only ponzi coin created to exchange through its system like Hextracoin, Bitconnect, etc.
Some scam coins still give profit at first time, but finally, it creates a big scam to earn all money it spent in the past.