The Baby's Here:
New Arrival Etiquette page 2

Don't expect to be fed.
This is definitely the time to offer to cook or drop off dinner (preferably without you staying). If you do stay, keep it short and make sure to clean up entirely. Either way, have zero expectations that you’re going to be catered to, because they will be very busy catering to baby.

Don't complain that the grandparents (or anyone else) are getting more time with the baby. 
This isn’t the time to keep score. A new mother may prefer to have her mother around, or instead may want her in-laws to help out with the baby. Even if your feelings may get hurt, this is a time to respect what works best for the new parents.

Adhere to "the schedule".
They’ve just figured out the best times to feed, bathe, and let baby rest. Support this amazing pitter-patter feat. Although you may prefer dinner at seven, serve it at five if the new parents find that works better for them.

Don’t be a know-it-all about the baby.
Finally! It’s your turn to hold the baby, and it instantly starts to cry! Before you list off your expertise as to why, there are a couple of things to consider. For example, the baby isn’t acquainted with your unfamiliar smell, or you might be holding the baby in an uncomfortable position, or baby just wasn’t ready to leave the previous person holding it. Try to avoid giving a list of your opinions in general. The parents know when the next feeding time is, whether the baby is cold, and whether the baby is tired. In other words, avoid any declarations such as: “He’s hungry!” “He’s tired!” “He’s cold!” Which leads to…

Avoid the phrase, "But I raised two kids!" (or similar). 
If it’s been a couple of decades years since you raised your children, not only has a lot of conventional wisdom changed, but you might also be out of practice. Think of it this way: If you tried to apply for a job that you haven’t had for 20-plus years, you’d likely be put through training again.

Even if you have recently had babies, try not to impose your child-rearing practices on them. It’s up to the new parents to decide what works best for THEIR babies. And keep in mind that every baby is different.

Adapt to changes.
There’s no way to predict how new parents will feel once the baby actually arrives. If that big dinner party they thought they’d be able to throw suddenly gets cancelled, be understanding. If they invited you to spend the night, don’t be surprised to find yourself looking for a last-minute hotel. 

Don't comment on either parent's decision to return to work (or not).
For many women (and men), this is an incredibly difficult decision. There are many factors that go into deciding, so support their choice whether or not it’s your own. Remember, when it comes to business, it’s none of your… well, you get the point.

Don't touch the baby. (If you don't know the family.)
Oh, how babies bring joy in the most surprising places. If you happen to come across one in the grocery store, park, or anywhere else, make sure not to touch the baby. Coo from a reasonable, hands-free distance.

Etiquette aside, here’s all you really need to know when it comes to a new baby: Be supportive, be sensitive, and be sure to respect this overwhelming and exciting time in the new mom and dad’s life.