Help! How to get baby to sleep?

Got this question from a reader:

How do/did you get your baby/babies to take naps? Mine has been awake almost the entire day from 9 a.m. until about 6 p.m. with a quick 20 min. nap at daycare. Now he’s so tired he’s mad fussy! What helped you???

What say you, readers? Can we help this mother out?