staying hydrated is the biggest difference for me. you want to make sure your pee is pale yellow. aim for at least half your weight in ounces in water/day. eating healthy fats and protein. almonds avocado etc. steel cut oats/oatmeal
letting him sleep is fine. i wouldn't let him go more than 5-6hours though. and if you're breastfeeding, pump during his usual feedings so you keep your supply up