So, you didn't mention how long you were going to be in town.  

Many of the well reviewed providers that are in Vegas tend to want some assurances before agreeing to meet you.  It usually takes a day or two of advanced notice for them so if you're not staying long, that's probably not going to be an option for you (hey, I could be wrong, maybe someone will take a last minute first timer).

So, tips for next time:

1) Do some research in advance.  If you use TER, they have a fairly large review database to look through.  You can narrow down your choices by selecting looks and services that meet your needs.  The search and reviews are more accessible if you pick up a VIP membership ($20/month).

2) Contact the providers well in advance.  Give them an idea of what date and time works for you and if you know where you're staying, give them that info as well.  If they have an appointment form (or contact form) on their website, it's probably one of the better methods to make the initial contact.  Email or a phone call works too if you provide the same info.  Being polite and discreet in your communications is important.  If you want to know what kind of services are available, read the reviews since they usually won't talk about specifics (you get too graphic or suggestive, they'll ignore you).

3) You can do the usual Vegas newbie that didn't plan in advance experience:  pick up some of those business cards they pass out on the strip and call them.  Or find an aggressive woman that wants to talk to you at the bar about "having some fun".

The alternative is to go the legit way and drive or get a ride to Nye County to a licensed brothel (Pahrump is closest with the Chicken Ranch and Sheri's Ranch being the two near there).  Also a rather unique experience for someone whose a Vegas newb.

Good luck,
 Bob