for me, selling at lower price is their mistakes and buying at pump price is bad habit. you can always buy at lower price then hold if it is go down to 50% then buy again. Never sell at loss!
Holding stubbornly no-name, pump and dump coins just because some time ago it made 500% is not a good strategy.
Overtrading, not doing TA properly, getting scared by shakeouts, taking losses too seriously, being overly confident when in profit, adding to an already bad position, setting stop losses where it'll most likely be hunted, trading when the market is choppy, using too high leverage, being impatient.
You must be: patient, savvy, "strong handed", and sometimes a contrarian.