I don't believe that your blanking out is a memory problem. From my experience as a student, many students who 'blanked' during exams did so as a result of psychological stress. What made it worse is parents expection. I know people who have aced school by using these simple tricks:
-Review notes immediately after the lecture. A lot of us seem to assume that it's unnecessary to review notes immediately after a lecture, because you just had the lecture, and you still remember SOME things. But the reality of the situation is, when you review the notes immediately, you are doing two things 1) reinforcing the information 2) raising questions regarding the notes you took. This will give you so much time to research your queries further. The thing is, the moment you understand your topics, you can ignore the notes until the final exam.
-Do not stress out. This was the ultimate secret for many acers in my universtiy. They never stressed out. They wre so cool about the exams, it felt like they were going in to play a game. When asked, all they could say was, "Why stress out? It's just an exam. That doesn't determine my success in life. bill Gates was a colege dropout and he still succeeded. I'll give it my best shot, but that's it." Coming out of the exam, they would normally come out with the highest grades, because others' had blanked out while they were idly answering with heads on their hands on the table.
-consult a councelor to find out if it's really a 'memory' problem, otherwise you'll be wasting money.
-Connect the unconnectable. Be creative while studying. I nkow people who made cartoons out of science subjects and science terminologies and aced exams that way. The more bizarre the cartoon is, the more memorably it becomes. There are more tips on creativity in:
-I really hope it helps. I am not an expert in memory, but I did brefriend a lot of Engineering A students.
IGNORE INC.: NUTZ 101: Introduction to Creativity