For income, I put a portion into high-dividend stocks, and either draw the dividend or trade them away pre-dividend for more than the dividend would have paid... re-buying later after the price drops post-dividend.
For short-term money trades, I look for depressed stocks with what I call rebound-potential... e.g. something like bad news or earnings miss can depress a stock 5-20% depending on the day/mood of the market, I buy and hold some of these I think have a potential rebound in a moderately short-term ( say a week or 2 ), for a modest profit.
The main thing is to stay diversified, and always keep some cash available to buy a potential dip, you cannot have all of your money in 2 or 3 stocks and expect to do well unless you're extremely lucky, and just like in Las Vegas, luck doesn't always go your way. The more and different stocks that you hold, the easier it is to sell a winner, and re-invest that profit in the next.
Also, you need to be able to hold through the short-term market flux, and not sell out of fear... i.e. kim jong shooting fireworks over Japan can shake the market temporarily, you need to be able to hold steady until the market recovers, and even better, buy the dip.