Here is a Neighborhood Map of Manhattan that I usually post to tourist-y questions ... most recently (9 months recent) here: http://www.theeroticreview.com/discussion-boards/new-york-2/re-manhattan-neighborhood-map--267656
.
There are slight disagreements about specific boundaries, but use it as a guide. It should come in handy when communicating with potential guests.  
.
"Are you anywhere near SOHO?"
"SOHO? What and where is SOHO? Let me see ... oh ... there it is. No, I'm in Midtown, closer to Murray Hill."  
(SOHO is SOuth of HOuston Street" In NYC, Houston is pronounced like House-ton not like You-ston = Houston, TX)
.
A Street x Avenue intersection is usually enough to help someone plan their transportation and scheduling. "I don't want to give you my exact location yet, but it is near 33rd and 3rd (thirty third and third)." In a Brooklyn accent ("th" becomes "t" and the "r"s disappear), that would be "toidy toid and toid".    
.
The shape of Midtown on this map is sort of a pink coffee mug, with the handle near Clinton. Other maps have slightly different shapes and boundaries.  
.
For your own convenience:  
The AVENUES run North-South.
- Mostly, the one-way directions alternate Northbound and Southbound.  
- Broadway (N-S) runs at a weird angle that cuts across from the West side (~10th Ave.) at  W 218th St. southward to the East side (~2nd Ave) at E 3rd St. (and further south to the tip of Manhattan).  
.
The STREETS run East-West. Fifth Avenue separates the East Side and the West Side. Building numbering on the East Nth or West Nth Streets begins at 5th Ave.:
Hudson River - 500+ West Nth Street - 5 West Nth |5th Ave| 5 East Nth Street - 500+ East Nth Street - East River
.
Keep your Easts and Wests clear when talking to potential visitors!  
If you mistakenly send someone to 5 West Zrd St. instead of 5 East Zrd St., it's not a big deal. They just walk across 5th Avenue and they are there!  
.
If you mistakenly send someone to 500 West instead of 500 East, it can take them 30 minutes or MORE to get across town! If they are mistakenly at 500+ West, they might even just cancel rather than fight traffic getting across town.  
.
Distance-wise, 20 "Streets" on the main grid are 1 mile. That is, to walk north along Nth Avenue from 34th St. to 54th St. is one mile. That can come in handy if you want go sight-seeing or get to a recommended restaurant or whatever. If you are 28th and someone says the restaurant is at 33rd, that's an easy 5 blocks = 1/4 mile (as long as it's on the same or nearby Avenue).  
.
I'm not remembering the East-West distances from Avenue to Avenue (e.g, 6th Ave. to 7th Ave.), but it's longer than Street to Street (43rd to 44th).  
.
As a one-time NYer, I do have one other request and recommendation. Newbies and tourists tend to look upward at the skyscrapers but PLEASE DON'T STOP IN THE MIDDLE OF THE SIDEWALK AND BLOCK US LOCALS FROM WALKING FAST!!! Thank you!
.
Have a fun and enjoyable trip to NYC!