Some of these approaches require short selling stocks; the trader borrows stock from his broker and sells the borrowed stock, hoping that the price will fall and he will be able to purchase the shares at a lower price, thus keeping the difference as their profit. There are several technical problems with short sales - the broker may not have shares to lend in a specific issue, the broker can call for the return of its shares at any time, and some restrictions are imposed in America by the U.S. Securities and Exchange Commission on short-selling (see uptick rule for details). Some of these restrictions (in particular the uptick rule) don't apply to trades of stocks that are actually shares of an exchange-traded fund (ETF).
If the strategy is within your risk limit, then testing begins. Manually go through historical charts to find your entries, noting whether your stop loss or target would have been hit. Paper trade in this way for at least 50 to 100 trades, noting whether the strategy was profitable and if it meets your expectations. If it does, proceed to trading the strategy in a demo account in real time. If it's profitable over the course of two months or more in a simulated environment, proceed with day trading the strategy with real capital. If the strategy isn't profitable, start over.
ECNs and exchanges are usually known to traders by a three- or four-letter designators, which identify the ECN or exchange on Level II stock screens. The first of these was Instinet (or "inet"), which was founded in 1969 as a way for major institutions to bypass the increasingly cumbersome and expensive NYSE, and to allow them to trade during hours when the exchanges were closed.[6] Early ECNs such as Instinet were very unfriendly to small investors, because they tended to give large institutions better prices than were available to the public. This resulted in a fragmented and sometimes illiquid market.

Make a plan to trade this strategy in a Simulated Trading account for 1 month to test your skills. Your objects will be to achieve a percentage of success (or accuracy) of at least 60%. You also must maintain a profit loss ratio of at least 1:1 (winners are equal size on average as losers). If you can achieve these statistics, then you are positioned well to trade live. During the 1 month of practice, try to take 6 trades per day.
News provides the majority of opportunities from which day traders capitalize, so it is imperative to be the first to know when something significant happens. The typical trading room contains access to the Dow Jones Newswire, constant coverage of CNBC and other news organizations, and software that constantly analyzes news sources for important stories.  

Head over to websites like Reddit and you’ll see many trading dummies who will often fall at the strategy hurdle, taking the first momentum examples they see and losing money left, right and center. Savvy traders will employ day trading strategies in forex, grain futures and anything else they’re trading in, to give them an edge over the market. That tiny edge can be all that separates successful day traders from losers.
Liquidity - The liquidity of a market affects the performance of scalping. Each product within the market receives different spread, due to popularity differentials. The more liquid the markets and the products are, the tighter the spreads are. Some scalpers like to trade in a more liquid market since they can move in and out of large positions easily without adverse market impact. Other scalpers like to trade in less liquid markets, which typically have significantly larger bid-ask spreads. Whereas a scalper in a highly liquid market (for example, a market maintaining a one-penny spread) may take 10,000 shares to make a 3 cent gain ($300), a scalper in an illiquid market (for example, a market with a 25 cent spread) may take 500 shares for a 60 cent gain ($300). While there is theoretically more profit potential in a liquid market, it is also a "poker game" with many more professional players which can make it more difficult to anticipate future price action.
Another trading method is known as fading the gap at the open. When the opening price shows a gap from the previous day’s close, taking a position in the opposite direction of the gap is known as fading the gap. For days when there is no news or there are no gaps, early in the morning, day traders will take a view on the general direction of the market. If they expect the market to move up, they would buy securities that exhibit strength when their prices dip.
Define and write down the conditions under which you'll enter a position. "Buy during uptrend" isn't specific enough. Something like this is much more specific and also testable: "Buy when price breaks above the upper trendline of a triangle pattern, where the triangle was preceded by an uptrend (at least one higher swing high and higher swing low before the triangle formed) on the two-minute chart in the first two hours of the trading day."