1. Speak to your baby in a high pitched voice. Adults tend to use this way of talking naturally when speaking to babies. It's called "parentese" and studies have shown babies are attracted to it.
2. Don't use "baby talk". Simple sentences are O.K. at first, but don't use incorrect grammar or your child's "baby" words. Describe what you are doing, where you are going, and who and what you are going to see as you are going about your daily routines.
3. Encourage your baby to make vowel-like and consonant-vowel sounds such as "ma", "da" and "ba". A good way to do this is by repeating what your baby says and then waiting for your baby to repond. This also teaches turn taking.
4. Respond to any attempt your child makes to communicate. When your child starts saying single words, expand on it. For example, if your baby says "Mama", you can say "Mama is here. Mama loves you.".
5. Encourage eye contact and do activities that keep your baby's attention on your face. Silly facial expressions, imitating your baby's facial expression, playing peek-a-boo, and holding objects your baby is attracted to up by your eyes are all ways to do this.