Study groups are small groups of students meeting outside of class to discuss details of lectures, to exchange class notes, to work on assignments, to study for tests and exams, or to assist in other ways with a course. Students report they find fellow students a very valuable resource when working on student strategies for their course work.
Students tend to learn more through discussion and questioning and sharing.
Study groups may be formed by students talking with classmates outside of class. It is important you feel comfortable working with the other members in your group. Yet, there is no need to limit yourself to your existing friends. Also, a group can benefit from a diversity of members - ages, genders, ability levels, experience with the subject, personality types, learning styles, among others. Working in groups of four is suggested by some authorities but you will likely need more to start with because some students may drop out and others may not be able to attend every meeting.