From a father of two for new fathers: 1. After birth your wife will be fragile as hell - help her get to the toilet, (mandatory!) back her up when she's taking shower (she can pass away). 2. Prepare mentally for baby blues - when your wife will be crying with no particular reason. She may say things that are sad, hurtful, scary - it's not her, those are her hormones speaking/crying. Withstand it. 3. Be patient. No, not like that. More. Your wife will be stirred by hormones and emotions. Your baby only knows how to eat, poop, sleep and cry. When you feel your temper is getting short - take a quick walk, scream, hit a tree, curse, whatever. And be back with more patience. 4. It's very probable that you will be the one who will bath and clean your baby for first month after birth. Do not think too much. Do it calmly and do not be afraid. 5. Get used to "stand-by mode". For a very long time you won't sleep few hours in a row. More likely you will get 40-50 min. long naps.

I need to add, to the person above that said he wished he knew babies cry for no reason. They don't. Be attentive and try to figure it out. Sometimes they're feeling lonely or scared and need to be held. Sometimes it hurts when poop is building in their intestines. If mom eats spicy food after giving birth, baby may love the flavor, but will cry "for no reason", due to the capsaicin in the spice burning their throat, tummy, guts, genitals and a**s. Sometimes their backs are itching, those really nasty itches that make you drop everything and reach for a back scratcher/run to the nearest doorframe to do the Baloo dance (jungle book reference, bear scratching back on trees and things). Sometimes acid in their tummies is just creeping into the esophagus just enough to cause heart burn, and the need to be vertical. Sometimes it's a trapped burp. Sometimes it's a nasty bout of gas. Sometimes they're too hot or cold. Yes, babies do get overheated and sometimes require to be cooler.