Hello mate.
When I daygame in my town, bookstores are one of my favourite places - particularly as one has a café. Quite a high proportion of my lasting relationships actually come from bookstores (that, is, not ONSs).
Most of these, my opener was something like:
"Hi"
"What you reading" (Actually this is my usual one)
"What you drawing".
You don't need to do things you wouldn't normally do. Just have a normal, interesting conversation with a bit of push-pull. Where possible, flirt, but I tend to save this towards the end or in day 2.
The key is to set up a day 2 or insta-date. For me, this is the secret to day game. Numbers mean jack all.
I think maybe it varies geographically but at least here in England bookshop girls have been quite open to me. If you're congruent and just start talking to them, often they will stop and start talking to you back...it's a nice place to have a chilled out conversation. I find some of the most interesting girls come from here too.
Oh, and for a laugh, pick up one of those funny self-help dating books and use it as an opener. I've had surprisingly good success with this - the first time I did it, I just expected to be rejected and did it as a joke to this lone wolf:
Gamble:
(With book in hand, pretending to read it really slowly and lamely) "Errmmm...excuse me.....uh......you have........really..........beautiful.............eyes? Eyes...yeah eyes....you have beautiful eyes..." (It didn't actually say that in the book, I just thought it was funny).
HB:
"Thanks, you have nice eyes too
"I was like...wahay! Sit down, match body language, and off we go! (Turns out a group of my guy friends turned up and sat with us and burned the set. Oh wellies!)