Here is the item again:
During the fall semester, parking on campus is very
difficult,
students circle the lots like vultures, waiting for an empty space,
and most students soon realize that taking a 7 a.m. class, despite the effort
it takes to get up that early, at least cures their parking woes.
The comma between difficult and students creates a comma splice. At this spot, there are two main clauses joined with a comma alone, making a major sentence error. Parking on campus is very difficult is one main clause. Students circle the lots like vultures ... begins the next main clause.
To fix this problem, you could put a period after difficult and capitalize the S that begins students.