When someone does great work, tell everyone, not just their manager. Do it in public and clearly in standups after they talk about what they did last day/week.
"I just want to mention, that work that Joe did on that module is fantastic, thanks!" It is so easy to be a force for good.
Being the person who does this evenly for all good work is a guaranteed way to make others feel better, work better, and to develop real friendships. People tend to know when they are working hard.
Compliment in public, correct in private.