If the prospect of learning a ton of signs overwhelms you, just pick a few you can will use consistently. Once you know those signs well, add one or two signs at a time. Here are some easy areas to work in a few signs:
Eating time is a great time to use your signs. Great signs to use are: MILK, EAT, MORE and ALL DONE.
Here's Nate at lunch time signing BREAD, CHEESE and PLEASE (he was enjoying homemade pumpkin bread with cream cheese):
It looks like someone is prompting Nate off screen, but nobody is there!
He's looking at the pictures on our computer screen saver.
Learn a couple signs in your baby's favorite story. Sign while you read. I like to sit Nate on my lap facing me and rest the book against me so my hands are free. Animals are always big hits. DOG, GORILLA and BEAR were the first animal signs that Nate learned. BOOK and MORE can also be incorporated at story time.
Try teaching SLEEP and TIRED while you put pretend to put your baby's lovey to bed. Nate gets a big kick out this and loves putting a blanket over his stuffed animals. This is also a good way to teach HURT. You can have a stuffed animal fall down and get a boo-boo. Then you can sign HURT on the animal's boo-boo. Don't forget to kiss it and make it better!
If you are looking for a book on how to begin using sign language with your baby, I highly recommend Baby Signing 1-2-3: The Easy-to-Use Illustrated Guide for Every Stage and Every Age. Want an online ASL dictionary? Check out http://www.lifeprint.com/asl101/general/dictionary/lexicon.htm.