Hi guys, thanks for your replies.
I haven't looked at minimum scores for many schools, though Brown does not have a minimum requirement, which is good.
I know I'll have at least two great LORs to send in: one from a professor who I took a seminar on fascism and totalitarianism with this past spring (with my thesis paper being an examination of the cult of personality of Benito Mussolini), and the other professor being someone who I've aced two classes with and with whom I'm doing an independent study on Chechen history. I just need to figure out a third professor for an LOR. Would the academic adviser for my school's history club suffice? I've been the treasurer of the club since last fall, so while I don't have class experience with the guy, I do have other experience with him which may reflect in a positive LOR. Would that be a good idea to go for, or no?
Other than that, I fear that my resume isn't as impressive. I'm likely starting a position as a conversation partner for non-native speakers at the Academic Resource Center at school, and I'm also going to start an internship at the campus archives either in the fall or in the spring, but other than that, I don't think anything would jump out. I don't have much work experience in any history field, so I'm a bit panicky about that.