Take time off to be with your new baby
Take parental leave if it is financially possible for you and your family. Having a kid, even if you already have one, is a big adjustment. It will change your life in ways you can only imagine. You and your family need time to adjust. Taking time gives you time to get to know your child. Time to change diapers, go for walks, sleep on the baby's schedule and bond with your child. This time will set the pattern for your relationship with your child for the rest of your life. If you aren’t able to take parental leave, use vacation time. It may be possible to stretch out that vacation time by mixing vacation time and part-time work to give you more time at home over a longer period. This can make it easier to manage work by giving yourself permission to sleep when you are tired. It will also reduce the guilt of leaving your partner and new child at home.
Jump In - Even though you have no idea what you are doing
Parenting is a learned skill. Read all the books you like, spend time babysitting other kids, prepare as much as you like. Your kid will be different. Acknowledge that you have no idea what you are doing. The thing is, nether does your partner. It is a myth that women are automatically better at parenting. Parents get better at parenting by doing. Parenting is a moving target. Kids change constantly, especially the freshly born ones. Don’t leave the parenting to your partner, get in there and change those diapers.
Put away your good shirts*
*Editor's note: when I first read this I though it said "put away your golf shirts"...which would be exactly what my husband did after we had kids :)
Babies are messy. Some are veritable spit-up fountains. There will be diaper explosions unlike anything you ever thought possible. Diapers are usually pretty good containment systems, but not always. For some reason it is quite difficult to get baby spit-up out of clothes - not to mention poo. If you own clothes that last you more than a year and you plan to wear them outside the house, put them away or seal them in a plastic bag until you are out of the house. Get dressed at the office or in the backyard if you have to. It is the only way to keep them clean. The rest of your shirts will have spit-up stains on the shoulders for the rest of their existence.
You've heard about the lack of sleep that comes with parenting. What you don't hear is that sleep-deprivation will make you into a jerk. There will be days when you can't see straight and you have a pounding headache. For some reason other people will still try to talk to you on those days. You will manage some kind of response and it will likely be curt, abrupt and jerky. Just go with it. In time you will realize that most jerks are actually sleep-deprived parents. This period of sleep-deprivation will be over in 18 years and you can go back to being a nice guy then.
Learn to Change a Diaper
It may not have occurred to you before the appearance of your brand-new poop-machine that babies poop a lot. As it turns out they need diaper changes 1-14 times a day, providing lots of opportunity for professional development. Installing and removing the diaper is actually quite easy. It basically involves figuring out which is the front and which is the back. For disposable diapers the sticky tabs are on the back part and they stick on to the outside of the front part. Cloth and hybrid diapers can be more complicated, but not by much.
The real risks are related to what is in the diaper and what happens during the changing process. As mentioned above, diapers are a reasonably good containment system - for the most part. Sometimes they fail and sometimes those failures are spectacular. You will usually have a pretty good indication ahead of time that you are facing a situation that requires back up or an immediate bathing experience. There is nothing you can do to escape these situations. Just make sure you have appropriate cleaning supplies on hand ahead of time.
Two key things to remember when diaper changing: 1) If you have a boy, place a loose diaper or pee-tent or something equally useful to cover the penis. Pee comes out of the penis and inevitably that will happen when you are mid-change. To prevent the pee from getting in your mouth, cover the penis. 2) If you have a girl, wipe front-to-back to avoid getting poop in the vagina.
So get in there and start changing diapers. - you'll be doing it for years!
Support your partner
Growing and getting a baby out of a body requires a certain degree of work and trauma to the human body involved. If your partner has just gone through this process, there will likely be some big hormonal swings and mood changes. These are normal. Be supportive while her body and hormones adjust to post-pregnancy and into motherhood.
Sometimes the mood changes are outside of the range of normal and suggest more significant needs. Keep any eye out for persistent depression or anxiety. Talk with your partner about how she is feeling and if you both agree that something is not normal(?) help her get the support she needs. She can talk to her family doctor about possible solutions, and in some communities there are support groups for post-partum anxiety and depression.
Umbilical cord stumps are freaky
The umbilical cord is apparently an important part of the whole baby cooking process and perhaps equally important to the belly buttoning of a kid. But the cord stump is a freaky thing. It may make you think of a loose thread. That leads to questions like - What if you snag the cord and the baby comes apart? Folding the diaper away from the stump is important. The whole thing only gets freakier as it starts to come off. Fortunately the stump usually only lasts a week or so. Once that loose thread falls off the fresh new belly button will be revealed.
Accept help and food
People are great. Especially when babies are involved. You will likely discover people who want to come and help you in some way. People will bring food so you don't have to worry about burning the house down by falling asleep on the stove while making dinner. People will offer to do your laundry or clean your house. It is ok to accept help. It is not a judgement on your abilities as a parent. People just like to help, and those who have been through life as a new parent and emerged out the other side are often looking for opportunities to pay forward the support they received. It is also ok to set limits.
Protect Your Time
Some people who want to help, would also really like to see and maybe hold your new baby. You and your partner need to decide when you are willing to see other people. If your partner has given birth, you need to protect her space and time to heal, and you might need to be the bad guy and say no on her behalf to eager family and friends who want to descend on you in the days after birth. When you do allow people to come for visits, set limits. Limit how long they come for and when they come. An hour of visiting is usually lots in the early days. You will be tired, your partner may be in pain if she has given birth. You will probably be ready to see visitors sooner if you have adopted a older child and aren't dealing with post-birth recovery and/or newborn sleep deprivation.
Sleep with a baby on your chest
Everyone who has ever held a sleeping baby already knows this and wants a piece of the action. There is something soothing about a baby asleep on your chest or in your arms. Perhaps it is because it forces us to slow down so as not to wake the baby or maybe they have magical healing powers like the purr of a cat. Lying on a couch with a baby asleep on your chest is pretty well the best place to be. This is the best part of being a new dad.
A new kid is going to change your life in ways you haven't even imagined. Each kid is different and everyone's experience is different. There will be unexpected joys and challenges. There will be things you have to do that you've never done before, and your partner is in the same boat. It is essential to communicate with your partner about how you are each feeling, what you are experiencing and what you are learning. This will set the pattern for how you function as parents and the example you set for your kid(s).
Have Fun (bonus tip)
Living the dad life is a crazy ride. It will be filled with unimaginable highs and incredibly frustrating challenges. You will discover emotions that you didn't know or forgot you had in you. You will learn something new everyday. Take the time to live life through the eyes of your child. Sing songs with and to your kid - even if you think you can't sing. Play with blocks and make funny faces and just make time to find the fun and joy of being a dad, no matter how challenging your day is.