Another thing that has helped me, and I'm sure many might say this is a bad idea, is taking Benadryl an hour before going to bed. Not only does it make me sleepy, it kills my sex drive at the same time. Without it, there were many nights where I was tired as heck but so sexually frustrated I couldn't sleep. Like any "advice" you hear on any message board, consider the source (amateur well wishers) and use your best judgement before following.
The most important thing a father can do for his children is to love their mother.