she accepts same-day appointments.  Many ladies do not accept same-day appts as they need time to screen their clients and cannot always do that quickly.  Personally, I like to set my dates up at least a week ahead of time, not really a fan of last minute dates.  If you don't know if she accepts same-day appts, you might ask, but be prepared to be turned down.

Swim

First, read their website, top to bottom.  Then contact them, telling them how they came to your attention, and that you have read their site.

Be prepared to give them all screening information that they ask for, and ask them if they can meet on a specific day and time, adding that you can be flexible if that is true.

Of course, the more notice you give, the higher your chances are; but some gals do see guys on the "sperm" of the moment, as they like to put it.

Also, share a bit about yourself, briefly that is.  It helps with the good feelings you want to engender.

Remember, spelling and grammar count.

...based on very little info.  
Does she have her own website?  
Is her website a fly by night deal or one she takes time and pride in?
Is she an active member of the community or does she just have dozens of reviews from fellas but hasn't a clue about them?  
Does she present herself like a lady or does she seem/look/act/appearance lean more towar the shady side?
Is she young? Too young to be handling all that this biz entails alone? Maybe someone is running her show....avoid.
Maybe she has a pimp that'll fuk your day up if something goes wrong so no need to screen?
If she takes her biz serious (you can tell the ones that do vs the ones that do not) then she is likely very resourceful.
That being said, we pay good money (extra overhead expenses) to stay on top of our game. This way, we all stay safe.
I'm thinking she screened you very well, discreetly...
You're a smart man for thinking with your big head...kudos..keep it up and you'll have a blast when you meet the ladies cz you'll feel comfie n safe!!
(totally gotta find my eyeglasses....sorry for any typos..lol, brb)
Peace & Lov

Just communicate like a human being with half a brain!!

Hey ya wanna fuck?
Lets hook up?

Those will get ya in the ignore box everytime, if you have a relationship with a lady sometimes a quick one liner can be a bit fun and flirty. But on first contact you need to show you aren't a douchebag. Something like this,

Molly McHooters,

Hey saw you're ad on ter, noticed you might be available on the 12th. I would love to meet you if we can work things out. I can provide references and P411 info as I'm sure you'll want to check me out. I look forward to meeting you.

Have a great day,
John Blueballs

See not that hard, you should get a response back if she has availability or not. Then all ya gotta do is provide references or P411, DC info etc. maybe a bit about yourself, age, height,weight nothing major.
Just like the real world a little tact and common sense goes a long way.
Now go forth and fornicate freely!!!

Make sure you READ the lady's ad/website thoroughly to see what her preferred method of contact is. Some ad sites require that we list our numbers/email addresses, but I for one state very clearly in all of my stuff that appointment requests need to come to me via my website's contact form. Anytime someone emails/texts/calls me directly wanting an appointment, it becomes obvious to me that he didn't read my ad/website, and therefore missed a lot of pertinent info. We take a lot of time and effort to write up our content, so it's just common courtesy to read it. That's probably my biggest pet peeve in this business.