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.
Day trading poses a number of hurdles. Mainly, each trading day is slightly different. Traders need a method that works in nearly all market conditions. That doesn't mean a day trader will win every day. On the contrary, even with a great method, there still may be several losing days a month. Winning every trade or every day isn't important, it is winning over the course of each week and month that matters.
The next important step in facilitating day trading was the founding in 1971 of NASDAQ—a virtual stock exchange on which orders were transmitted electronically. Moving from paper share certificates and written share registers to "dematerialized" shares, traders used computerized trading and registration that required not only extensive changes to legislation but also the development of the necessary technology: online and real time systems rather than batch; electronic communications rather than the postal service, telex or the physical shipment of computer tapes, and the development of secure cryptographic algorithms.
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.
You're probably looking for deals and low prices, but stay away from penny stocks. These stocks are often illiquid, and chances of hitting a jackpot are often bleak. Many stocks trading under $5 a share become de-listed from major stock exchanges and are only tradable over-the-counter (OTC). Unless you see a real opportunity and have done your research, stay clear of these.