Most Helpful Girl
Get down on one knee infront of her in a semi-public place, pause to look at her lovingly and pull out a jewelry box with the tickets inside and say "will you... go to the Luke Bryan concert with me?"
Haha no dont do that. When she's at work send a bouquet of flowers with a card and the ticket attached to it. Then she'll have something to brag about to her coworkers. Or put the ticket in her coat/pants and if she hasn't checked throughout the day, then tell her there's a surprise in her pocket.0
Most Helpful Guy
I assume she likes Luke Bryan. I would put the tickets in a book and ask her to look up something for you and have her turn to the page (all while you're really 'busy') she'll see the tickets and freak out. You could also put them in her purse so when she reaches in, she'll see them but make sure not to bury them. You could also tape them to her mirror in her bathroom. It really depends on her habits and how crazy you want to get in surprising her. You could also give her a present to open, so after she tears away the paper and opens the box, there's nothing inside. Then you go, 'oh yeah, I have them right here!' and you hand her the tickets. Limitless ways of surprising a girl0