Thanks for the tips I need to slow down I try to go to fast. But I do hit the main safety points
Everyone gets nervous the first time or three. Dealing with customers in teh dive shop etc helps give you confidence with chatting to strangers - which is all you are doing
1. Own the brief be confident in yourself and you will appear confident to the guests (even if you don't feel it)
2. Inject some humour without being over the top - don't' be a mono-tone robot. I always joke to my guests, that we already have their money so we don't feel any obligation to bring them back ... Also feel free to get them to chuckle at your expense
3. Make it flow from start to finish in a logical order and pause between each point -
4 Hopefully you'll have a dive site plan to help describe. If not draw one in advance
5. Use the cue card to make your own bullet points
6. Make it interesting - if its dull you'll lose them which will put you off your stride.
7. ask for questions at end, they might ask something you forgot
I personally get the boat to congratulate the DM after their brief, and then pick up anything they've missed "I'd like to add..." I'll then council the DM in private with positive and improvements but am always supportive of the DM in front of the guests.
It's okay to make mistakes, we all do....
And yes practice beforehand