Trouble improving on practice

[Gmm21]

I've been doing Big Book sections for verbal and I have done about 10 or so in the past week. I cannot seem to really improve on the number I get wrong. It usually goes from about 12-15 wrong. I don't know why I can't seem to improve, I am also studying vocab every day as well. I usually get a few wrong scattered in each part so it's not like one type of question that I struggle with. Maybe it's test management? I dont know, but if anyone has advice I would appreciate it.