Get to the point quickly: lengthy introductions may cause your listener to turn off before you arrive at what it is you really want to say.
Don’t go over the top with praise: if you something critical to say, opening your remarks with some comments about the persons strengths can help to defuse a defensive response, but laying it on too thickly will smack of insincerity.
Don’t apologise: by all means acknowledge that you have something to say that may not be entirely comfortable, but profuse apologise give the message that (1) you have right to say what you are saying, and (2) what you are may not be valid.
Check the other persons understanding of what you have said: any defensiveness on the part of the other person will increase the chance of misperceptions.
Be proximate: feedback is best delivered as soon after the event as possible. If the message is a critical one, then waiting until the next review meeting comes around smacks of harbouring bad feeling. If the feedback is positive then it will have a far more potent effect on performance if it occurs immediately following the behaviour.
Be specific: often as givers of feedback we hide behind vague comments that difficult to challenge but also impossible to unpack. These are not helpful at all. The receiver needs to precisely what it is about his or her performance that is not working well so as to be able to do something about it.
Own what you say: don’t hide behind organizational policy or the reported opinions of senior people.
Deal with what is achievable: for all of us there are limits to how far and how fast we are able to change. A shy and tongue-tied interviewee is not going to be one leap. So give people things they can get hold of – incremental steps that they will take them along the road to the ultimate goal. Don’t load them with too many points either. It will be disheartening for them and will probably mean that none of the recommendation get tackled properly. Recognise also there may come a stage for everybody where personality or ability will permit no further change.
Deal with behaviour, not with people: if you are giving feedback that may interpreted as critical, be sure that you are focusing on the behaviour and not the person. Avoid labelling people with expressions