When you must deliver criticism about someone's work, it's best to be direct rather than diplomatic. Avoid the all-too-common practice of mixing positive messages with negative ones. It's confusing to the recipient. Steer clear of the classic feedback "sandwich," which goes like this: good news, followed by bad news, ending with good news. Eating a sandwich with good bread — but bad meat in the middle — isn't too enjoyable. And while giving someone feedback in a considerate, contextualized, and balanced manner is good practice, you need to be very clear on the poor performance part or your message might get lost. It is often the most important aspect of a feedback session, so don't muddle it.