* Over trading-- it's very important for a day trader to limit the number of trade he/she took in a day.
* Lack of trading plan-- develop a strategy an stick to it, do not ever enters a trade blindly, if not the market will remove you blindly.
* Failure to use stop-loss-- to me it's the most important thing I do while trading,
Risk management must be well mastered by a trader. Likewise with other technical mastery that has to do with trading.
For me, overtrading, trading plans and stop losses will be mastered when someone who wants to do trading work is willing to explore knowledge by learning about basic tips and so on which are the main capital, whether the activity is carried out individually or working under the control of a company.