Here's some of the things we've learnt in the last 4 months with our little guy.
He's always slept - but in the first couple of months he thought that 4am was bedtime, and midnight to 4am was time-to-scream-lots. The other 20 hours he was lovely.
He's now pretty much given up the screaming, and got the hang of bedtime at a slightly more civilized time too.

-He needs noise to sleep more easily - shopping centres, birds singing outside, daddy snoring, music, whatever. He prefers to be able to hear us - so he has sleeps in the lounge during the day
-movement also helps (going for a walk during the day is pretty much guaranteed to make him snooze a bit, and it makes me feel better too)
-putting him on the floor with a boring toy is usually more effective at getting him to sleep during the day than putting him in his cot
-if Mum has more than 1 cup of tea in a day she will pay with a very awake baby.....
-there is no point trying to settle him if he has a "stuck fart". He'll eventually doze off, but wake again very grumpy a little while later. Much better to take the time to deflate first (either lie him on his tummy and rub his back, or lie him on his back and rub his tummy - or both)
-office swivelly chairs are good for rocking babies without breaking mum's arms
-He can be hungry very often - he sleeps best after feeding every hour or 2 in the afternoon and evening
-Feeding to sleep works best if both Mum and bub are lying in bed, and if I wait a bit after he has gone to sleep before moving him. These feeds can be very long (40+ minutes a side, with a lot of it appearing to be him sucking in his sleep) but they pay later 'cause he sleeps longer
-Feeding lying in bed means that Mum can have a bit of rest whilst feeding
-He doesn't like being wrapped - initially he slept better with his arms free, now he wants to be able to kick easily too

Can you get your DH to look after bub say from 5pm till he's too tired - and at least have some snooze yourself then??

Good luck
Kate