Just one safety meeting or one in a series? If just one then there is no way you can cover everything so you need to proritise. Find out what causes most accidents and concentrate on those.
Where I hang out most, the tower people provide a barbecue every year. Nothing like free burgers to get out a bunch of pilots, and of course the payback is we get to listen to ATC tell us what we are doing wrong, and how to do it better! Works very well, nobody goes away without having learned something positive to do with safety, so some sort of bribe to attend should be included.