As Target’s executive vice president of merchandising since 2008, Tesija and her team strive to keep every square inch of the retailer’s shelf space profitable. Target built its rep on affordable style. But what can make or break a retailer is the hard work that customers don’t see—keeping track of buying habits, running and interpreting sales data, and devising strategies that give price-conscious customers what they need. Walmart has been Target’s top competitor. Tesija and company will also need to keep on eye on a resurgent J. C. Penney—where former Target marketing star Michael Francis is now a top honcho.