and while you are there. That will help you immensely.

Don't brush your teeth with tap water. Use the free bottled water they give you.

Try all kinds of Chinese food. It tastes better than it looks. I had the best BBQ Pork I've ever had last week in Hong Kong. Dim Sum is really really good.

When traveling to Shenzhen just take the MTR to Lwo Hu or Lok Ma Chau. You can walk across the border there. Just make sure you already have a ride or get in the taxi line. Don't just take the guys standing there yelling at you "taxi". They aren't really taxi drivers. Just guys that use their own cars. They always make me nervous... like they take you somewhere and meet up with their friends and beat you up and take your stuff.

If you are going in and out between SZ and HK then take extra immigration forms and fill them out before you get in line. Also, always pick the line for foreigners that's next to the residents or special lane. As soon as those people all go through they start taking people out of the next line over... which is your line. Get through immigration faster.

Not much to go see in China. Just do your business and you'll be fine.

In Hong Kong there are a ton of things to do.

Victoria's Peak. On Hong Kong island. Take the little train up and enjoy the tourist trap at the top of the peak. Do this on a clear day if there is such a thing in HK.
Temple Street Night Market. On Kowloon side. Lots of junk to haggle over and some good food.
Star Ferry. Take a trip one time on the old ferry boats instead of taking a taxi or the MTR to HK or Kowloon.

If you want to know some great places to eat (western food) I can give you a list if you need it.