Congrats! OB is the best nursing specialty, in my oh-so-biased opinion
My advice is to ASK QUESTIONS and orient for as long as they will let you. Never, ever hesitate to ask for clarification. OB is a world apart from med/surg, and no amount of OB rotation is nursing school will prepare you.
How many deliveries does your unit do each month? Just remember that birth is an inherently normal occurrence, and most women and babies would be fine without our help. Women are designed to give birth, and generally speaking, the best course of action is just watchful waiting. We tend to make things worse when we interfere with nature's design. We are there in case the sh*t hits the fan; there is no need to meddle when things are working on their own.
When I admit a mom, I ask her if she has any specific wishes for her labor and birth, and I bend over backwards to help her have the experience she wants. I also tell women straight up that birth is unpredictable, and that sometimes things just don't go the way we want them to. In my experience, the most important thing is to be kind, supportive, and honest. Women who report a negative birth experience usually relate it to feeling like they didn't know what was going on or they didn't feel listened to. Even when a mom comes in wanting a natural birth experience, if she ends up with a difficult delivery, she will be much more likely to feel positive about the experience if her nurse (and midwife/OB) is caring, supportive, and empathetic.
If a mom wants a natural birth, DO NOT continuously offer her pain meds. It is *hard* to watch a patient in pain, because our instinct is to take that pain away. I tell moms who want a natural birth that I will *not* offer them anything for pain. I outline their pain management options when I admit them, and tell them to let me know if they want anything. Then I do everything I can to support them during labor to keep their pain manageable. I am lucky enough to work with some midwives who allow women a normal diet during labor, and we have standing orders for intermittent monitoring if the mom is low risk and their admission strip is good. Intermittent monitoring may seem like a minor thing in the grand scheme of things, but moms who aren't tied to a monitor have more freedom of movement, and allowing moms to change position ad lib is HUGELY important in pain management. Moms who need continuous EFM, or whose providers don't allow intermittent monitoring, can benefit from using the tele unit.
Take a doula class- the ability to provide knowledgeable, hands on support to your patient during labor is a valuable skill.
Also- if your hospital still does that stupid crap where they hand out formula goodies to all new moms, be very aware that this practice has been shown to reduce breastfeeding rates. I ask my breastfeeding moms if they want the bag full of samples, and I encourage them to give the samples away if they really want to continue breastfeeding long term.
Also- encourage babies to spend their first hour on mom's chest. All of our Very Important nursing stuff- weighing, eyes & thighs, etc, can wait until after the family has had a chance to bond and baby has nursed at least once. Initial assessments can be done on mom's chest.
Look up "Baby Friendly" Certification. Try to incorporate their guidelines into your care, even if your hospital is not "Baby Friendly" certified.