What developmental milestones should I watch for in the first 3 months?

By 1 month: lifts head briefly during tummy time, responds to sounds, focuses on faces within 8–12 inches. By 2 months: social smiling, tracking objects with eyes, cooing sounds. By 3 months: holding head steady when upright, opening and closing hands, bringing hands to mouth. All babies develop at their own pace, so ranges are normal. The AAP screens for development at every well-visit. Consult your pediatrician if your baby doesn't respond to loud sounds, doesn't smile by 2 months, or seems unusually stiff or floppy.