One of the most effective ways to gradually weave sign language into your communication is to be on the lookout for teachable moments. If, for example, your child reaches for a ball, she is communicating with you that she wants the ball. This is a teachable moment. Take the time to label the word ball, verbally and in sign, then give her the ball. Say and sign the word several times as your baby explores the ball and looks to you for reassurance and information.
It's fairly natural to add labels when we communicate with babies and young children verbally. For example, think about what happens when the kitty walks into the room (or a bird perches on the porch railing, or a dog passes by when you are playing at the park . . . ). Your baby will likely look at the kitty (bird/dog), then look at you expectantly. Without even thinking about it, you will probably say something like, "That's the kitty. You like that kitty, don't you?" The only thing that's different when you are signing is that you would also sign the word, kitty/cat (or bird, or dog) during the conversation.
The main trick is that you need to develop a sign language vocabulary so you are "on the ready" when these teachable moments present themselves. As I mentioned in Tip #3, take a moment to think about what your child is most interested in (and/or what you see a lot of and/or do a lot of during the course of a day). This will help you narrow down some priority vocabulary words that match with your child's interests and activities.
Once you've narrowed down some vocabulary words that you want to focus on, start singing! Hands down, that's the easiest way to build your sign language vocabulary. I've written several posts about singing and signing. Click here to link to an article that's a good starting point on this topic if you need some guidance in this area.
Lastly, make sure the teachable moments you are taking advantage of do not have the makings for a power struggle. If your baby is especially eager to receive the ball, she is not going to be very happy with you if you hold back on sharing the ball just so you can sign ball. Likewise, if your baby is really hungry, he is not going to be very patient with you if you insist on signing more before offering each bite of food. Take advantage of teachable moments, yes, but keep the tone playful. If this proves difficult, start out by signing primarily during playtime, and then ease into other contexts.
So what are you waiting for? The next teachable moment is just around the corner. Happy Signing!