Day traders generally use margin leverage; in the United States, Regulation T permits an initial maximum leverage of 2:1, but many brokers will permit 4:1 leverage as long as the leverage is reduced to 2:1 or less by the end of the trading day. In the United States, people who make more than 4 day trades per week are termed pattern day traders and are required to maintain $25,000 in equity in their accounts. Since margin interest is typically only charged on overnight balances, the trader may pay no interest fees for the margin benefit, though still running the risk of a margin call. Margin interest rates are usually based on the broker's call.
There is a commonly quoted statistic that only about 5 percent of day traders succeed. This is a good approximation. Most people who try day trading will not succeed, yet most of them do not practice everyday for six months to a year either. Time investment and quality practice increase a day traders chances of being in the 5 percent that are successful.
Trending stocks rarely move in a straight line, but instead in a step-like pattern. For example, a stock might go up for several days, followed by a few steps back during the next few days before heading north again. If several of these zig-zag patterns are strung together, and the chart appears to be moving higher with some degree of predictability, the stock is said to be in an uptrend.
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.