Sorry, but this is simple.
Depending on ur age there are different reasons for not paying. Although, if u are on a first date girls ARE going to have a picture in their head of whats going to happen (and yes, K and an F close will b floating around in there). They also have a picture of the normal guy pays, he takes my coat etc etc etc. Now, you are different to most men she has dated, u are unique and therefore of value. Yet on a first date if u come across as an arrogant arse or just cheap then her picture of how this date ends changes.
Now, here is the real easy bit. You WILL pay. I ALWAYS pay. I have some money to throw. I dont make a deal of it since its ONLY money. however, when i am paying you have to make her do (or preferably pay for something) for you. Therefore you paying isnt u trying to buy her out or what ever, ur just rewarding her

I'll use a movie as an example (bad First date idea btw)
while we are at the till:
Me: ok i'll grab the tickets, u sure ur brave enough to watch this *poke* (brave if its a horror, or some other comment just as a little joke)
Her: bla bla bla *poke n giggle*
Me: anyways, pointless us standing in line twice!! go grab us some popcorn and a drink and i'll meet u at X in a sec.
*she goes off. then u meet up*
Me: awww, whoes a good girl *in a voice like ur talking to a young girl or a pet* You have this go fetch thing down to a tric

dont need to put u on a leash do i

. Well anyways here is ur ticket so lets go!!
Tada, yeah, get the idea right? good boy

(joking

)
/madals