Trouble latching and sucking

Sorry if this is a repeat--no time to read through/search.  LO is 5 days old and half the time nurses beautifully.  The other half the time he either latches but doesn't suck or sucks on anything but the boob and refuses to latch.  Last night I sat up with a hungry baby for 2 hours while he rooted and sucked on his hands and sleeves but refused to latch on.

 Any hints on helping to get him to latch when he is hungry and calm but refusing to do so?  Or on getting him to suck when he actually does latch on?

I know he is eating well (lots of wet and poopy diapers), but it would be nice to be able to feed him during the night and go back to sleep rather than sitting up half the night waiting for him to eat.

 Thanks!