The profit potential of day trading is perhaps one of the most debated and misunderstood topics on Wall Street. Internet day trading scams have lured amateurs by promising enormous returns in a short period. The idea that this kind of trading is a get-rich-quick scheme persists. Some people day trade without sufficient knowledge. But there are day traders who make a successful living despite—or perhaps because of—the risks.
Scalpers need to be disciplined and need to stick to their trading regimen very closely. Any decision that needs to be made should be done so with certainty. But scalpers should also be very flexible, because market conditions are very fluid and if a trade isn't going as expected, they'll need to fix the situation as quickly as possible without incurring too much of a loss. 
Day trading is speculation in securities, specifically buying and selling financial instruments within the same trading day, such that all positions are closed before the market closes for the trading day. Traders who trade in this capacity with the motive of profit are therefore speculators. The methods of quick trading contrast with the long-term trades underlying buy and hold and value investing strategies. Day traders exit positions before the market closes to avoid unmanageable risks and negative price gaps between one day's close and the next day's price at the open.
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.