What are some of the most innocent ways a girl can turn you on?  

honey, leave your wallet behind. today is one me     LOL ..   ok serious now --- just sit quietly and undress me with her eyes.  

When a lady in a dress crosses her legs and the dress runs up her dress.  Usually most girls don't even know its happening.

me with that innocent, come-on look.

a provider won't convince me and will think she's doing it on purpose.
nobody flirts with me anymore.
but buck a million years ago:
seeing that she's not wearing panties under dress and opening legs, camel toes, hair sticking out of bikini area, feet , sandalsand stuff like that on purpose or not.  
i don't get amazed easily anymore but I still look.

Tight fitting of course. From beat cops to firefighters, women in uniform do it for me.

The right look, can thrill me to the core: leave me breathless, heart skips a beat and captures my imagination.
Sometimes, something as small as a whispered comment can light me up and give me goosebumps and cause a certain swelling.

Agree with that. A whispered witty comment. Ashley Shye type of lick lick comments.  
But here is where I get angry. Most women I have known, talked to or seen in real life or TV  
is that they are very easily offended and or take everything too seriously.  
Things are much worse now for what they say. Not just women but men too. They say everybody is a snow flake.  
So whatever but providers are good actresses and they can play along. They see the faults of "normal" women and take advantage of it, good for us.

when a woman unzips my fly, pulls out my dick, and starts sucking it by accident.  I agree its only "innocent" if its an accident on her part.   It hasn't actually happened to me yet, but I know when it does, I'm going to be really turned on.  

I still remember looking over and spotting this pretty girl across the room at a wedding.  I don't remember if her dress rode up a bit, or she pulled it to adjust her stockings, but that flash of white lace against her thigh got me right there.  One of the only times I ever picked up a girl at a wedding.  We dated for about 6 months after that.