h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

The neatest place in New York City to go for Dim Sum is Triple Eight Palace, located under the Manhattan Bridge in the Triple Eight Mall (East Broadway under the bridge; F train to E Bway). There are no windows to distract you; instead there are ceremonial banquets going on constantly. I went once for a weekday lunch with my Swedish boss & our Chinese coworker; the Swede got a little uncomfortable when the sheep brains came to the table.
The only advice I would have (probably for dim sum restaurants in general) is not to order too many dishes at once. Lots of times the more interesting dishes are on only one cart, and that cart could spend 30 minutes making the rounds of the dining room. So you should be patient in order to sample the full range of what's available.

Original article author here:
This is very true. My model for Dim Sum is several wonderful restaurants in Los Angeles' Chinatown and the incomparable Yank Sing's in San Francisco. In all these places the cardinal rule is WAIT. Don't fill up on something before you know what else is circulating. And don't be afraid to say no to carts that have been by before while you wait for the rarer menu items. The staff usually does a good job of presenting everything, but remember what you've seen before and wait for something new. You can also ask for particular dishes you want and it will come by double-quick.

Another Dim Sum tip: if you're not sure you'll like an item, or are just filling up, ask for a "single" or a "one person" order. Most Dim Sum items are meant for two people. You'll find when you ask for a single that the server will take out the tongs and transfer half of the serving on the cart to your plate (you'll still often have two units on your plate). This can also save your wallet if you're sampling Dim Sum alone for the first time.

-Hikehitcher