Some of the common mistakes that scalpers make are poor execution, poor strategy, not taking stop-losses, over-leveraging, late entries, late exits and overtrading. Scalping generates heavy commissions due to the high number of transactions. A per-share commission pricing structure is beneficial to scalpers, especially for those who tend to scale smaller pieces in and out of positions.
Assess how much capital you're willing to risk on each trade. Many successful day traders risk less than 1% to 2% of their account per trade. If you have a $40,000 trading account and are willing to risk 0.5% of your capital on each trade, your maximum loss per trade is $200 (0.005 x $40,000). Set aside a surplus amount of funds you can trade with and you're prepared to lose. Remember, it may or may not happen.