K.L.
Well, he is a little young to transitioning him to 2 naps a day, but he should be napping for longer and more consistantly than he is now. Most babies sleep their best a short time after their feedings, so try putting him to sleep 15-20 minutes after he's had a full feeding - and at this point, you CAN keep him awake in order to ensure he'll need a longer nap.
Also, where does he nap? If the room he sleeps in is too quiet, he may need some white noise to help him fall asleep so that he can't hear all the goings on of the house (use a fan, or a white noise cd. My baby LOVES her fan). If you put him down in a place that is too noisy, he may need to sleep in a quieter room. My daughter doesnt sleep well if where she is napping is bright, natural or unnatural life - but every child is different. Try putting him down in different places and see if you can find out where he sleeps best. Try introducing a "lovie" if you haven't already (a pacifier, blanket, or stuffed animal). Also, try letting him cry for a few minutes if he wakes up too soon from a nap - he may just need to fuss for 5 minutes or so to put himself back to sleep.