For history papers, the basic rules of English grammar apply. One of your best resources is the IUP Writing Center which provides one-on-one tutoring and word processing at no charge. The center is open to all students, faculty, and staff for assistance with writing. It is a quiet, comfortable place for writers to work.
Here are some additional resources to help you along the way:
Common Errors in English
The Elements of Style, William Strunk, Jr.
Guide to Grammar and Writing