You are going to need to get better grades than 90% of your classmates.
There's really no other answer. You can write a great exam answer, but you still may not be relatively good enough to be in the top 10%. Further, what might help one person get good grade may not help you. The most general advice I think I can offer is to make sure you're diligent about doing your work and not falling behind, make good outlines using past years' outlines as a guide or reference, do as many practice exams as possible, and try to have your professor critique at least one so you can get some direction as to what they'd like to see you do better.And I don't understand why you'd be surprised at the caliber of students at your school. That's pretty insulting to them, as I'm sure you don't appreciate people thinking you're any less intelligent or competent just because you go to a T3 school.
I desperately want to make it into the top 10% of my class for two reasons: A top position in my class would certainly help when it comes to career options, and also for the purposes of possibly transferring to a higher ranked school.