Am a few weeks ahead of you (my son is 9 weeks) and he was a terible sleeper for the first couple of weeks. Sometimes he was only getting 6-8 hours sleep in 24 hours (so much for newborns sleeping on 16 hours a day). Anyway he has become a much better sleeper for the past month or so. Basically I made made it my number one priority to get him napping during the day.
Try to get him back to sleep an hour and a half after he wakes. Try everything that is suggested. If the usual rocking, bouncing, singing etc doesnt work and the time is ticking on I get him into the pram and go for a walk or get on the bus. These things usually send him off.
I know most people like to bath their babies before bed to help them sleep but I try to squeeze a nap in before the witching hour/cry time of around 6pm, so I give him a bath around 5, this usually send him off to sleep for a couple of hours and then I wake him gently around 8pm to change and feed before bed.
If he wakes early on in a nap dont make eye contact try to quielty rock/shh/burp back to sleep. Quite often it is a fart or a burp than has woken him and he just needs a little comforting before going back to sleep.
I have found that if he isnt asleep by 3 hours after he has woken up then he becomes overtired and it becomes even harder to settle him and he cries a lot more than when he has had slept well during the day.
He also had problems with wind but it seems to have settled somewhat, but he still farts a lot though, especially in the morning and this upsets him. Google some youtube videos about baby massage and try bicycling his legs and gently rubbing his tummy in a clockwise direction. This really settles him now and he likes it. Lots of smiles from him!
Goodluck this is working for me so far, am now waiting for it all to change again though. Am wondering when he will decide naps are no longer needed once again!