here's what works for me:

I use the free section at stockcharts.com to identify technical support levels on the stocks I buy.  I often look for horizontal support which is easy to identify with the aid of a t-square type tool that comes up when you check the inspect box at the top of a chart.  Check it out.  Sometimes I place a stop below that horizontal support or just below the middle bollinger band (dotted line) which often acts as good support when a stock is moving higher; bollinger bands are an option in the overlays section.  Then there are Matt or Steve's triangles, which frequently act as support or resistance, as do moving averages.  Play around with all these to find what feels best to you.  Never expect to sell at the very top and learn to trust your instincts. 

Perhaps more important than any mechanical approach is to insure you only trade when everything else in your life is going well.  Otherwise, your judgement may be clouded.  Learn from your mistakes (we all make them), keep things simple, never have regrets and always look ahead.

Good luck.