Congrats on your first. It will be like nothing you've ever experienced.
Off the top of my head...
1. Most, if not all, parenting books are bunk. However,
buy this book and feel free to thank me later when your child will (literally) sleep on demand.
2. Don't be a cliche and avoid diaper work. Offer to change as many as you can (especially in the wee hours of the morning). This will make your wife's life so much easier and give her something to brag about to her friends since none of their husbands do that.
3. Tidy up around the house as much as you can. Second sentence of #2 applies here as well
4. Support her 1000% on whether she wants to go nursing or formula. If she's insistent on nursing and is having difficulty making it work encourage and support her through it.
5. Get up with her in those wee hours to help out. Even if your just by her side she will appreciate the support. Even if she insists on letting you sleep through it all, still get up occasionally. Eventually it will become second nature.
6. Yes, you need 20 different tote bags and at least 5 different diaper bags. They will all function the same but somehow your wife is certain the next one will be the right one. Go with it.
7. Never feel bad about not being able to "keep up with the joneses" in relation to the developmental progress of your little one. It's not a race, but if there's a finish line, it's how they turn out as an adult, not that they can speak Swahili by 6 months. The other parents are most likely embellishing a bit anyway.
8. An obvious point, but reduce "guy time" or "my time" significantly. It's now family time. Guy time will return but can still be peppered in occasionally. Insist that your wife gets her girl/my time instead. "My time" is now your commute to/from work. And the long way to the grocery store.
9. You can watch the child. By yourself. For an extended period of time.
8. Have
fun. Its a hell of a ride.
9. Don't blink.
10. Learn to love espresso.