Read a bunch of books. Don’t trust old people.
If you are on the ball, you can pretty much do anything you want for the first 6-9 months. They are a just a lump that poops. Strap them to your chest and go about your normal life. Go places! Play games! Do all the things.
Know that there are good times and bad times, and the extremes extend themselves with age. The good gets better and the bad get worse. Cleaning a shitty diaper isn’t fun, nor is waking up at 2AM, but just get over it and do it. The good times of an infant aren’t all that exciting either. You get some smiles, some laughs, it’s nice. Fast forward, and now your lump is accomplishing major real-world things that you are so proud of (yay!) but also struggling with real world shit (oh no!). Enjoy each step of the journey.
Brace yourself to enter the world of “other parents.” Up until now, you have selected the people you associate yourself with. Now, you are lumped into a group with a very low bar to entry: unprotected sex. You don’t need to be friends with all of the other parents.
Make a list of all the things you learn, and all of the potential strategies you could be implementing as a parent. Should you be really strict about bedtime, diet, or any of a hundred other different parenting areas? Make a giant list of all the shit that seems important. Then rank it. Draw a cutoff line somewhere in the middle. Above it, you will be really strict. Below it, you will do the bare minimum but generally be lax.
Know that (especially in the early years), something that is “below the line” for you might be someone else’s number 1. This will probably be a dumb old person or another dumb parent, but it could be anybody. They will treat you like you are murdering baby for not being strict about item #72 on your priority list. Fuck these people. Disassociate yourself from them. Hold your line.
Maintain your boundaries with family. Don’t let them smother you. Don’t ghost your friends.