So you and your wife/partner are expecting, congratulations! This is likely both exciting and terrifying as a new expecting father. I wanted to write up a guide of sorts for new dads who are expecting their first kid.
Slow down:
First things first, do your best to slow down and just enjoy the ride. While this can be true of most things in life, the journey to and through parenthood really goes by in a flash. You'll be stressing about which car seats and strollers to buy, how to decorate the nursery, and whether you're listening to the right kind of music while they're in the womb. Before you know it, you'll be headed to the hospital for the delivery, then you'll be taking the baby home, then celebrating their first month, then their first steps, first words, and before you know it they're in school. Take pictures to remember them and their milestones, but also take time to put the phone away and be in the moment every step of the way.
Go to the appointments & Support your partner:
Take time off work if needed, be with your wife/partner for her appointments, see the ultrasounds. This will be the first chance you get to "see" your child. I know for me the first time I heard the heartbeat is when it really felt real to me. Also realize that your wife/partner is going to be going through a lot of changes both physically and mentally. Be there to support them through these changes.
Educate yourself:
Take a parenting class or two. Learn the basics of swaddling, breast feeding, feeding, general sleep requirements/expectations. Read some books, preferably written in the past 20 years that doesn't rely on dated parenting advice. I won't delve into which books to read, as that is a topic for another conversation.
Be ready for change:
Yes, having a baby is a big step. Be ready for your entire world to be flipped on its head. There's a reason the first couple of months is referred to as being in "survival mode". Let the housework and chores slip. As long as your baby has its needs met, and you're able to nap and shower and care for yourself, you're doing fine.
Pack your bags:
Have a go bag ready once you get into the 3rd trimester. While the majority of kids are born within a week or 2 of their due dates, premature babies are not uncommon. Be prepared to drop everything, grab your bag, and head to the hospital at a moments notice. Exact items for the bag are a topic for another conversation, but you should at minimum have a few changes of clothes for you and the wife, sheets and pillows for yourself, snacks, and items to entertain both of you for a long labor period.
Work on "nesting":
Once the baby is here, you and your wife will have zero time or energy for cleaning or chores. Try and do a full spring cleaning of your house in the weeks leading up to the due date in an effort to make the first few weeks of parenting that much easier. If you don't have to stress about a huge mess in the house, you'll be in a much better place mentally to care for your baby.
Do the dirty work:
Ryan Reynolds said it best. A human being has exited your wife; she's done enough. Do the dirty work, change the diapers, let her rest as much as possible. If she's breastfeeding, be there to support her, get her snacks and drinks, and take the baby once they're done feeding.
Try not to get hung up on milestones:
You'll have this urge/desire to compare your child to other babies every step of the way. Try not to get hung up on exact dates/deadlines for these milestones. Listen to your pediatrician, and ask their advice if you are concerned about any developmental milestones along the way. Not all kids crawl, some go straight to walking. Some are non-verbal for a long time, then you can't shut them up once they start talking. All kids develop at different rates. I would strongly recommend watching the Bluey episode "Baby Race" to really put things into perspective.
That's all I have for now. Feel free to throw in your own tips or anecdotes in the comments.
Id argue 90% of home ownership boils down to trying to keep outside air and water out of the house. If you can do both of those, you're winning the battle.