Honestly, go up and down every single row. Some houses have incredibly lavish booths with a lot of fun stuff to look through, and a healthy amount of galleys to give away. There are also author signings that take place in the booths, and there’s a special author signing area in the back of the center.
I would highly recommend downloading the BEA 2013 phone app (free), it makes finding booths a lot easier, and it gives you a schedule of all the author signings/panels that are happening.
Have fun tomorrow! Oh, and everything is ridiculously expensive at Javits. I made the mistake of forgetting gum yesterday, and a bottle of water and a pack of gum was $7+.