I've always been one who sells to earlier, either to minimize my losses or to realize my earnings ASAP and leave. I've seen in most of my investments, if not all that if I would've just left the coins there they would've been worth 10-50x what I put in before. This is upsetting as a person and trader, as I see how much money I'm missing out on.
How do you traders do it, hold and hold and hold. Waiting around for more and more money?
Depends on what coins you are holding. Does it have strong fundamental? If you hold bitcoin, ethereum, ripple or other top 10 in coinmarketcap.com you are good to hold for a long term.
To overcome your fear, you have to be able reading the market especially bitcoin. When bitcoin crashes, you should sell your coins as soon as possible to prevent bigger losses.