• over-trading
• too much leverage
• under capitalization
• not adhering to stops
• trading without a plan
• paying short thrift to proper execution
• assuming too much risk, not respecting it
• trading products I don’t fully understand
• competing where I have no edge
• becoming too emotional
• under-valuing the need for ample liquidity
• misaligning time-frames (the time a trade typically needs to play out, versus my expectation/need for it conclude)

Successful traders fail all the time. In fact, many even fail a majority of the time. The difference is that their failures are not a failure to execute their plan. The failure rests in the fact that the expertly chosen trade turned out to be wrong (nobody can be right 100% of the time – except Congress). And when the trade was wrong, they took their loss which resulted in minimal damage to their portfolio and moved on to the next opportunity.