Baby Whine or Baby Sign?

I just got a question from my sister, Amy, about her little girl (16 months, I believe)
"Right now Natalie only knows a few words but she wants to say so much more. She is always crying at me for things but I know she would not if she could ask me for them. I know this is the perfect time to teach her just a little sign language. How do you go about doing this and what few would you recommend."
I took a baby sign class a few years ago and used it with both my children and found it EXTREMELY useful. Here are a few tips I learned from my class:

• Just start out with a few signs at first. Try the words that might interest your child the most and that you will run across frequently. I always started with milk, eat, and more.  But if your child LOVES dogs or crackers or candy or anything else you could start with one of those.(Be sure not to introduce more than a few until they grasp the idea. Don't overwhelm them!)
• Make sure to do the sign right in front of your own face. That is where they will be looking. If you do it down or off to the side they might not notice it as much.
  
• ALWAYS emphasize the spoken word as you sign. Even when they use the sign a lot, you must always say the word aloud. (This reinforces the word and will help them learn to speak it as well. If you do not say the word aloud as you sign, they might not learn how to say the word.)
  
• Don't give up. It takes a while for them to get the concept and it might seem very tedious, but be persistent! (Unless, of course, they learn to say the word. Then you can move on.)
• You can start signing to them as early as you want. In my class they said start at about six months but I got a little bored of it when I was teaching my first because it was a long time before he could sign back. I started a little later on my second child. They also said some kids as young as 8 or 9 months learn to make some signs themselves but I never had any luck until they were closer to a year. You can start when they are a little older too and can already say some words. It will expand their vocab until they are ready to verbalize the words. 
• Watch their hands closely. Sometimes their sign won't look exactly like your sign, but they still might be trying to reproduce it.
  

I know some people worry that teaching babies to sign delays their speech but I don't think this is the case. We all teach our children how to wave good-bye and the still learn to say the word. We shake our head yes and no and they learn those words as well. As long as you emphasize the word as you sign it, I don't think they will have any trouble.
As far as learning the signs here are some places you can look:

• Books, books and books. If you don't want to buy them go to the library. This is a great, free option!
• YouTube has some great videos.
• I have flashcards from Sign Babies that I really like.
• Signing Time makes some baby sign videos but they are a bit spendy. (Again check to see what your library has.)
• Here is a chart online that I found.

Any questions? Did I leave out anything really important? Anyone have any experiences with baby sign that they would like to share? 
Good luck!