Mostly the same as the posters above:
#1: Get a doula. Although there are lots of great doulas who are just starting out, in your situation I recommend trying to find one with at least a few births under her belt at the location you plan to deliver at. She may be able to help you get the staff to be a little more flexible if they are famililar with her (and on good terms with her). If they know her, and know she knows the policies, it's also less likely they can try to push you into something that's not really required but that they just wish you would do--and they will know this too.
#2: Interview the OBs in person. First, you will get a feel for the office staff and the way the OB likes to operate just by making the appointment. You will find out right away if they are happy to take your questions, or if they act like it's a huge pain in their rear for them to make time for you to talk to the doctor. As a potential patient, they should be happy to answer your questions and discuss any concerns you have, not be annoyed by it. Second, at an in person interview, you will get a distinct feel for how the OB really feels about things, even if he (or she) tries to pretend he's more flexible than he really is. If you're asking for something and he warmly responds and assures you he can do that or work with you, it's great. If he hems and haws and try to give you a neutral, fence riding answer, you will know that he really doesn't like that or deson't want to help you with it for some reason, no matter what he says. And of course if he is openly hostile about anything, you can move on to someone else right away.
#3: Keep an open mind. Don't make the mistake I did and go into it assuming they will fight you on everything, or that it just won't be possible to have the birth you want because it's in the hospital with an OB. Be optimistic--don't set yourself up for a self-fulfilling prophecy. It's also possible there are some benefits that a larger facility like a hospital might be able to offer that could be really nice for you. For example, there was a chance my DH was also going to be deployed for this birth. I contacted the hospital in advance and asked about their policy on video during the birth and told them why (so my DH could at least watch the video if he couldn't be there). They replied and told me that not only do they allow full video of deliveries, they were fully equipped with all the necessary equipment to provide live, real time internet video which he could watch from his deployed location (assuming that location had internet access) so that he could watch the birth as it occurred. I hadn't even thought of that option, but I was glad to know it was there should we have needed it and that was definitely a big hospital "plus" for me.
#4: READING. Read everything you can get your hands on that's in support of natural birth. I particularly LOVED Ina May's Guide to Childbirth. I read it before I had DS, loaned it out and didn't get it back, and so bought a new one during this pregnancy and read it again. She has such a practical, natural approach to childbirth and I felt very at ease and confident after reading her book, both times.
I have had one hospital birth that was completely unmedicated and with no interventions, although I did have to deal with some unprofessional attitude from the staff. I am about to have my second birth any day now in a hospital and although it wasn't how I wanted to do it, I've made peace with my circumstances and am just happy to be meeting my baby soon.
Good luck to you and I sincerely hope you're able to have the birth you desire.
