Encourage your candidate to ask others for 360º feedback regarding the way he comes across in a group. What does the candidate do exactly and to what effect? What are his strengths and what could be improved? Discuss the results with the candidate.
Ensure that your candidate does not avoid situations in which he could meet other people but, on the contrary, looks for them. Ask the candidate to think on forehand what kind of impression he wants to make and encourage him to act accordingly. Evaluate what went well and what could be improved.
Investigate with your candidate why he finds it difficult to act in public. Is he scared? Is he afraid to make a fool out of himself? Is he overly concerned what others might think? Ask the candidate to reflect on the question what the worst thing is that could happen.
Encourage your candidate to pay attention to colleagues who know how to present themselves. Is there anything he can copy from them?
Let the candidate ask people around him what they perceive to be his qualities.