Unlike a number of day trading strategies where you can have a win/loss ratio of less than 50% and still make money, scalp traders must have a high win/loss ratio. This is due to the fact that losing and winning trades are generally equal in size. The necessity of being right is the primary factor scalp trading is such a challenging method of making money in the market.

The intraday trading strategy to be used also depends upon the traders’ personal trading styles, along with being dependent on the market conditions. Some traders are very active and do many trades a day, with large position sizes, catching even the small price movements; while there are others who trade only on specific news events or only on tendencies that they have well researched.
Although they’re usually not as orderly as an uptrend, downtrends also tend to move in a step-like or zig-zag fashion. For example, a stock could decline over the course of many days. Then it may retrace part of the loss over the next few days before turning south once more. When this behavior is repeated over time, the downtrend of the chart becomes easier to see. The move downward is the trend itself, with bear rallies or retracements being visible as the counter trend.
Years ago, when stocks were quoted in fractions, there was a standard spread of 1/16 of a dollar or a "teenie". This spread allowed scalp traders to buy a stock at the bid and immediately sell at the ask. Hence the teenie presented clear entry and exit levels for scalp traders. The scalp trading game took a turn for the worst when the market converted to the decimal system. The decimal system closed the "teenie" often times to within 1 penny for high volume stocks. This overnight shifted the strategy for scalp traders. A scalp trader now had to rely more on their instincts, level II, and the time and sales window.
Successful traders have to move fast, but they don't have to think fast. Why? Because they've developed a trading strategy in advance, along with the discipline to stick to that strategy. It is important to follow your formula closely rather than try to chase profits. Don't let your emotions get the best of you and abandon your strategy. There's a mantra among day traders: "Plan your trade and trade your plan."