I'm an FNP and I worked for a few years in adult primary care. That gave me the opportunity to see a broad range of conditions, and see what I liked. I discovered that I hated diabetes, cardiology, and psych, was ok with women's health, GI and ortho, and really liked ENT, pulmonary, and derm. I now work in an asthma/allergy practice which combines a bit of the three areas I really like. I also get to see kids again, which I like. I also got a substantial pay raise because I went from a community health center to a private practice. There are very few true specialty certifications for NPs-I've seen forensic, palliative care and of course the ANP, ACNP, Peds, WH, and psych tracks. Your best bet for working in a specialty is to find a position in a specialty practice where they're willing to train you. I'd recommend spending some time in a family medicine/internal medicine practice after graduation to get some experience and see what you like. Also, if you work in a general practice you will likely be referring to specialists in your area, and can make some contacts that way.