What are some tips for managing my baby's constipation?

Prune or pear juice. Try undiluted prune or pear juice. Watch here for more info http://www.Youtube.Com/watch?V=ff5l1zwqp8y.
Prune juice. I prefer to try prune juice (or prune baby food) first! babies love the sweet taste, and giving some every day can keep their stools soft. In younger infants, corn syrup, about 1-2 tsp, added to formula, can loosen stools as well. Breast fed babies very rarely have hard stools, so it's not usually an issue for them.