Once you place an order, immediately place a sell at a slightly higher price. At that price you wouldn't want to get in yourself anymore, it would be a price too high, a level too quickly reached, an entry would be deemed as being too late. If your sell price is not soon reached, you can hold onto it for a random swing triggering your sell order. Keep in constant touch with your position during the day and pe prepared with a stop loss for an adverse price movement.

Know the stock you're about to trade with (day traders like me usually bang on one stock per day). Make damn sure the stock you're dealing with isn't a loser (unless you plan to do some shorting). Watch the market as well if the stock follows the market closely (like one of the Dow stocks). Some tech stocks don't follow the market very closely at all and are prime candidates for day trading.

Look for stocks that are actively (especially heavily) traded and have big price swings in a single day (volatile stocks), these stocks are ideal day-trader material. Many volatile stocks will jump around during the day, giving as much as 2-3% change over the course of the day.