I am not sure what you are asking. Most of us here have some degree, Bachelor's, Master's, and/or PhD. History is a broad topic with many different areas. Technically I am not a "historian" but an Anthropologist with a degree in Archaeology. So off the bat you can divide the general topic of history into historians and anthropologists. Most will have a specific field or subdiscipline they work in and can speak on, but their degree will probably be a general field. If you want to study history, you just need to study history. Skills needed would include an ability to read and understand texts, being comfortable writing, and possibly a desire to do research on a topic that eventually you would write about and present to other members of your field. Whether it is for a degree or in your free time as a hobby, I would advise you study it because you love it and not to show others the error of their ways. Many people may see an academic and a know-it-all as the same, but I would argue the difference is in how you share what you love to study. If you only want to correct people and feel like the smartest guy in the room, that is not how these fields should be treated. Ultimately your goal is to further contribute to your field's understanding of topics, and to also share these findings with people outside your field. I personally love talking archaeology with people with any level of understanding of the topics, it is fun to teach people as well as see people get excited about history and what topics they are passionate about.

Not a standard answer here, but I would hope others who work in/study the past agree with the ideas listed. You study history by learning and then using what you learn to help others understand a topic.