How can I tell if my baby is tired?

Learn babies ques. In early infancy babies love to interact with their caregivers and have a hard time letting go of the aleart state. The drift thru wake and sleep states like an adult drifting off in a boring lecture. If baby is tired, they may fuss to let you know they are tired & want you to fix it. If you reduce stimulation and let them settle in their "tired place" they will often drift off.
Yawning. Some of the signs of tired baby are : 1. Yawning. 2. Fussing /whimpering. 3. Disinterested with surrounding/fixed stare 4. Partially closing his/her eyes. 5. Jerky leg movements. 6. Sucking fist.