I would recommend taking an OB review course. I recently took a review course to help me get my RNC-OB. I found if very helpful to myself, but I think it would be a great course for a new grad starting out in OB:
I would recommend taking an EFM course as well. The above link offers one as well as a general OB nursing course. I have the luxury of attended UCSFs (where most of the research and decisions in the new EFM Categories were
created) advanced fetal monitoring twice a year, being that I live in California. Where do you live? What local or semi-local education opportunities are in your area? Ask the nurses you work with how they get their CEUs.
I think the biggest tip though would be have confidence in yourself. OB departments are full of estrogen...the nurses can smell insecurity before you even get out of your car. Hold your head up, have confidence, but never ever have a "know it all" air about you. Remember what you learned in your preceptorship, but know that you can learn different tools from each nurse with whom you train.
Take notes, carry them in your pocket for reference. Are you doing just one department or all? I work in LDRP in a rural area with no MDs on site, so I had a lot to learn, note cards were my friends for my first few weeks.