The reason is because all too often the price can drop and you will end up giving up that profit. Instead, as soon as I’ve reached my first profit target (if I’m risking $100, then as soon as I’m up $100), I’ll sell 1/2 my position and set my stop at breakeven. This method of scaling out ensures small profits on all trades that move in your favor, giving you a better percentage of success.
The key to scalping while using short time frames is to identify price changes before the rest of the market has had the chance to act. You should also be willing to accept very low profit margins—gaining less than 1% on a given action will still usually be in your best interest. Because of this, many scalpers may implement tight stop-loss and stop-limit orders over time.  

A stop-loss order is designed to limit losses on a position in a security. For long positions, a stop loss can be placed below a recent low, or for short positions, above a recent high. It can also be based on volatility. For example, if a stock price is moving about $0.05 a minute, then you may place a stop loss $0.15 away from your entry to give the price some space to fluctuate before it moves in your anticipated direction.
Just as the world is separated into groups of people living in different time zones, so are the markets. If you start trading on the Cac 40 at 11:00 ET, you might find you’ve missed the best entry signals of the day already, minimising your potential end of day profit. So, if you want to be at the top, you may have to seriously adjust your working hours.
By aggressively trading on margin he can produce 5% daily profits on the 100k buying power he will grow their 25k cash at the rate of 20% per day. The risk of course is that he will make a mistake that will cost him everything. Unfortunately, this is the fate of 9 out of 10 traders. The cause of these career ending mistakes is a failure to manage risk.
Volatility is the name of the day-trading game. Day traders rely heavily on a stock’s or market’s fluctuations to earn their profits. They like stocks that bounce around a lot throughout the day, whatever the cause: a good or bad earnings report, positive or negative news, or just general market sentiment. They also like highly liquid stocks, ones that allow them to move in and out of a position without much affecting the stock’s price.
Day trading is defined as the purchase and sale of a security within a single trading day. It can occur in any marketplace but is most common in the foreign exchange (forex) and stock markets. Day traders are typically well-educated and well-funded. They use high amounts of leverage and short-term trading strategies to capitalize on small price movements in highly liquid stocks or currencies.
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.
This part is all up to you. There is no "line crossing," "arrow appearing" or "a small voice telling you to buy now!" You have to understand a little bit about how the price action works before you decide on your entry. Using our example, the Volume indicator shot up drastically meaning that traders are getting in on the action and thus driving the price upwards!
Swing traders should select their candidates from the most actively traded stocks and ETFs that show a tendency to swing within broad well-defined channels. Virtually all trading platforms provide a function to enter channel lines on a price chart. The trader should keep a list of stocks and ETFs to monitor on a daily basis and become familiar with the price action of their selected candidates.
It is important to understand the fundamentals of intraday trading in order to make consistent profits. A good tip is to trade with the current market trend. If the market is falling, sell first and buy later, and vice versa. Make an intraday trade plan and stick to the plan. Set your desired profit and stop-loss limit. Do not be greedy. Instead, book your profits at regular intervals. Maintain stop-loss levels. It helps you to limit your loss if the market does not perform. Also, choose highly liquid shares and trade in a small number of shares at a time, if you are not a seasoned trader.
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."