Students have their own method to study for examination.
... Studying is not limited to taking up exams. So I guess you should avoid that part.
Students have their own methods of studying.Some students prefer to study individually because of the privacy and owning scheduledmanaging time more effectively .
However, in my belief, I prefer to study in group for several reasons.
... when you say "in my belief", then you need to specify your belief like;
However, in my belief, I think that studying in a group is better for several reasons.
Or without the " in my belief" part it sounds fine. :)
In fact, through studying in groups, we might be affected by the other members' actions without self-discipline.
.... in fact you mostly tend to get distracted.
Since your opinion is in favor of group studies and you mention that there are several reason for that view, you need to talk about those reasons in the body para in favor of group studies. Your first body para is illustrating the opposite side of the argument and it would not help you at the exam. Stick to your opinion and support that side of the argument.