Write a personalized note to your boss. In a handwritten note, describe why you've enjoyed working for your boss and what you've learned under his or her guidance. If he or she is a coffee lover, throw in a Starbucks gift card. If you're worried about co-workers labeling you as a kiss-up, discreetly place the note and/or gift on his or her desk. "You're not trying to show off or make anyone else feel bad," Ranieri says. "You're just making that personal acknowledgement of what somebody has meant to you."