With a one year old baby, I have been using baby signs that are common in our daily lives such as milk, more, finished or all done, eat, nap, mama and dada.  As an example, feeding times is such a special connection with mama/daddy and baby.  When I cradle my child to set up for breastfeeding, I would sign milk.  I started when she was about three months old.  I continued repeating it at every feeding.  My husband reinforced the signing by using it as well when he would feed by bottle.  She picked up on the sign and was signing at 7 months old when she was thirsty.  Now with her at a year old, I still continue to sign every time I give her milk before giving it to her in her cup.  Getting in the habit of signing before giving your child something he/she may want will help your child associate the sign with the object.  It may take several days, weeks or months before your child starts to communicate for that object when he/she wants it.  Continue to use the sign once your baby uses it.  Include it as part of your daily lives.  Be patient… your child is learning every time you sign to him or her.  Give it time.  Babies can communicate physically 6 to 8 months before they are able to communicate verbally.