There are many common pattern seen in stock price formation on a chart. One that I would like to highlight today is the Cup and Handle (CnH). Here is a recent Weekly chart on KLAC (Kla-Tencor Corp) that shows a nice clean formation:
Notice the large Cup formation from March 2011 to Jan 2012, then a mild pullback, then a nice run back to test the highs (thus forming the Handle). Any traders with a Long position will want to see it hold the Horizontal Resistance line and then attempt a move over the $53 level.