While I'm nursing or eating, put an object close to me to look at. Slowly move it away. Because place-holding is holding myself ready to continue an activity that has been interrupted. It allows me to learn something about the object that was so fascinating. Play games involving naming the baby's body parts over and over.
Babies are hard at work whenever they are awake, trying to learn all about the world.
To help them learn, you should give them many different safe things to play with and inspect. Measuring cups and spoons. Boxes and plastic containers. Hold me gently and securely. You are the most important watcher of your child's development.