We got my 4 yo nephew into the show by placing a Star Wars hat on him and made him raise his hand and jump up and down. He got in no problem. He loved it. Great experiance for him and all of us standing in the audience.
My daughter 4 got picked in Dec. last year. She jumped up and down and got their attention. She didn't have a sign, we had one, but forgot it in the stroller. It is so cute!! Good luck!!
I truly believe a sign made the difference. DS made a sign (16" x 22") on poster paper that we folded and put under the stroller. I believe it is the only thing that got him picked. BOTH times he tried for it he was picked.
We got there about 20 min ahead of time so he could have a front row spot.
5 year old DS got picked a couple of weeks ago. We had a sign, a bright green hat, and got there early enough for him to be in the front row. Was the highlight of his trip!