There's no two ways about it - 2013 been a stellar year for shares of Walgreen ( WAG). The $48 billion retail pharmacy giant has rallied more than 36% since the calendar flipped to January, and now, there's reason to believe that WAG could be headed for even higher ground. Here's how to trade it... Walgreen is currently forming an ascending triangle pattern, a bullish setup that's formed by horizontal resistance above shares at $51, and uptrending support to the downside. As WAG bounces in between those two technically important levels, it's getting squeezed closer and closer to a breakout. When the move above $51 happens, it makes sense to be a buyer. The 50-day moving average has been acting like a pretty good proxy for support in the very short-term. If you decide to jump in after the breakout, that's a good place to keep a protective stop.