Top tip one -
Switch your state of mind on "I am going there to GIVE" - All our fellow human beings need to see that it's OK to show ourselves, with our qualities and our flaws. We all need to see ordinary everyday people dare and speak up! Go there to give... not to seek acceptance or approval. They need you to do what you're doing. Give your own light. You're a hero.
Top tip two -
Most of the time, the first row of chairs remain empty. Why? That is because they are scared too! They need reassurance, they need your acceptance and your approval. Offer them a great smile, tell them they are welcome, that they are great and beautiful , thank them for being here. Do what human beings do when they want to make others feel good, and they will do the same for you. Don't wait for them to start, they may not think of it.
Top tip three -
Make eye contact with those in front of you, with those on the sides, with those at the back.
When you make eye-contact, and smile while doing so, you break the ice. Then you will feel you're part of the group, instead of being just one isolated individual on this big stage. This will defuse nervousness. When you're not making eye contact, you can look between to persons. at shoulder's height.
Top tip four -
Less is more. The three tips above were twice as big before I started writing this fourth one. They could even become thinner. Keep everything short, talk slowly, make pauses. You know your subject, their brains need to process the new data you're providing. Slow down.
Top tip five -
If you look healthy, they will like you. If you can, take time to run, or practice yoga, relax or anything to make you feel good and healthy before getting on stage. Don't let anybody talk to you at length about loads of stuff beforehand. Breathe.
The first impression you'll make is very important. Open your arms, smile, look at them in the eyes and put good energy in a vibrant "Welcome everybody! It's good to see you there!" ... and the rest will follow.