I seem to be the first person to have read this message, I am probably the worst person to try & give advice!
But the way I see it:- practice, practice , practice & then practice again.
"spot" on something, that is to say find a point in the venue & focus on it, be it a flower or a door handle, keep looking at it & pretend it is in your bathroom & you are just practicing.
Run it past a few of your friends who will be there, so that they are not hearing it for the first time.
Good luck with this, I am sure more help will come your way.

Regards Skipy