I always refer to Analysts Rating and cross check with Morningstar Rating to have a gauge on the fair value of a stock. The average PE against its historical PE is also useful.
The saying of one should be greedy when others are fearful hold true in long term investing. When a particular stock price is battered due to negative news which is temporary and do not change the fundamental of the stock, that is when I will take opportunity. Example is $Salesforc...

July feels like Chinese New Year to me with lots of counters in red
My portfolio is heavy on technology and semiconductor stocks and hence took a plunge in July. Overall the portfolio still in green with non technology stocks such as UNH save the day. The July experience taught me that it's important to have a diversified portfolio with growth and defensive in different sectors. This is especially true when market is rotating out from technology stocks.