Consider what it is that drew you to history.
Is it the detective work of research? Telling persuasive stories? Geeking out over cool sources? Connecting with people in the past? Having a clear answer to this question might help you figure out which of your skills you want to build on post-graduation.
Learn more about graduate programs.
Really dig into the websites for these degree programs, and see what the course work looks like. Read some bios of professors or graduate students if available. See if you can find course syllabi. Do you have the prerequisites you need for the program you’re interested in? Should you be taking more language courses, for example?
Connect degrees to job titles.
It’s not always obvious how degrees connect to career paths. Some of the program sites linked here give examples of the kinds of specific positions their graduates enter, like this page from EMU's historic preservation program. Another strategy is to identify the kind of job you want and work backwards: find someone who has that job and see if you can figure out what degrees they have.
Try it out.
An internship or co-op or even a summer volunteer opportunity can help you figure out a lot—including what you don’t want to do.
Talk to people.
Ask around and see if you know anyone who has experience in the kind of program you are considering. Sometimes graduate programs will even put prospective students into touch with current students to ask questions.