A lot of the emails I get are from moms of poor night time sleepers. When we start talking, and going over baby's schedule, it usually transpires that these babies are not having good enough naps in the day. As counter intuitive as it sounds, a baby that doesn't sleep much in the day, will not sleep well at night. Some moms are even keeping babies up in the hopes they will sleep better at night. ...THEY WON'T!!!!
I cannot emphasize enough that a sleep deprived baby will become overtired and cranky, and will pass out from exhaustion, but not go into a normal relaxed, winding down phase, that leads to restorative sleep. Couple that with the fact that now adrenaline and other stress hormones are kicking in, and you can expect a disastrous night of broken sleep. Incorporate good naps into your baby's schedule, and you will find they sleep much better at night!