Speak clearly and sufficiently loudly – people will be more sympathetic if they can hear and understand easily
Smile and make eye contact with people to engage them with what you are saying
Take your time when speaking – aim to talk a little more slowly than usual to avoid rushing if you are nervous
Be brief: Make your point and then stop – avoid going back over what you’ve said
Be clear: If something sounds confused you can always say “I’ll make that clearer” or check if people have understood
Don’t apologise – it will make you seem less authoritative. Act confident, even if you don’t feel it!