Something to keep in mind is trying to make your baby stay awake longer during the day may actually result in a overtired baby. Overtired babies don't actually sleep better.
For me I have always considered a 4 hours stretch (at that age) at night "sleeping through" . I know (believe me, I know!) how frustrating it can be to have little sleep happening at night & a frequently waking baby.
Can i ask, are you breastfeeding? I found just going with the flow was less stressful then trying to enforce a routine. Sorry to offend anyone here but I don't actually agree with the feed/play/sleep routine. I never found I had any luck with it with my first baby & that trying to stick to it just made my life that much more stressful as my baby didn't like it either. Its one of those things as with all things parenting, you have to take it all on board & do what works for you & your family.
But back to breastfeeding, reason I ask is their is a chemical/hormone in BM that actually helps make the baby sleepy, it has the same effect on Mum too. the idea is that it helps you & bub get back to sleep after feeds.
The other thing with feeds, This would apply for FFing as well I would imagine. Keep your night feeds very quite & subtle. Keep any lights needed low key. A red or Blue light bulb can help give you enough light to work with but keep things dim enough not to make baby thing "Hey lets play!"
Also, have a think about things that may be causing your bub to wake. Is he waking because he is ready for another feed?? Is it because he is cold, or too hot?, could their be a noise waking him, or maybe is it too quite? Maybe a white noise could help. Even a small fan turned on in the room can help (of course during winter don't have it pointing towards him, just stick it in the corner facing the wall). You can even buy "white noise" CDs. Is he in your room? if not, try sleeping in his room for the night to just see if there is anything you notice that could be waking him.
Another thing you may like to try if you are breastfeeding is say he has a feed & goes down for the night at 6pm, has another feed at 8/9ish. When you head to bed, put him on the boob again, even if it was only half an hour ago he fed. Just see if he will take that little bit extra & maybe sleep a little longer so you at least get a little longer of a stretch before needing to wake again. It use to bug the crap out of me that I would go to bed around 10pm only to wake again just as I was getting into a good sleep at 11pm. Once I threw that extra feed in I was getting a better block of sleep because bub was getting it a little earlier & making through a little longer. So I would go to bed at 10, once bub was fed & nappy changed if needed I would be settling in by 10.30ish & getting a good go till about 2 - 2.30 am.

Anyway, I hope that something in there might have been helpful.