The time of day he goes down. Unlike newborns, who are more random daytime sleepers, babies around 4 months and up benefit from a regular naptime, says Marc Weissbluth, M.D., author of Healthy Sleep Habits, Happy Child. Shoot for a morning nap at 9 or 10 A.M. When your baby's 6 months or so, add an afternoon nap that starts sometime between noon and 2 P.M. The consistent schedule will help him wake up happy.
When he goes to bed in the evening. If your baby doesn't get enough sleep at night, he's more likely to wake up fussy from a nap during the day.
Our tip: if your baby wakes up cranky: Don't try to cajole smiles out of him. Instead, help him adjust with a low-key physical game (try bicycling his legs and singing a quiet song).