Four kids here, ages eight and under. The only advice that I give soon-to-be parents is to read the instructions on the website "My Baby Sleep Guide" before their baby is born and they're suffering from sleep deprivation and feelings of being overwhelmed and hopeless. The author is incredible, her website is a gold mine, but it's not very well organized so it takes some time to parse. As a starting point, I think these are the two most important pages...

http://www.mybabysleepguide.com/2010/02/sleep-problems-by-ag...

http://www.mybabysleepguide.com/2013/02/average-sleep-charts...