Are you even a mentalist? You cant ask what to do when you dont even know basic mentalism.
Anyway I suggest you do from mentalism (these are things ive done for 600) some basic mind reading. You let people sign things on papers and you predict them. Abnormal lift is a good thing to do and center tear is a good one.
PS. sorry if i was jumpy on the first half i just dont like that people think mentalism is easy.
Practically any book by Theodore Annemann contains lots of brilliant routines for very large audiences. I recommend "Practial Mental Magic".
Hope I've helped , not much of a mentalist myself, but I read some of his books and he's really brilliant.
there is a video of a live perofrmance of a very good mentalist here in the media section...maybe you cant perform like he does, but it gives you the outline of what you may want to have for a large audience.