If you know the material and are just a poor test taker, I would not be overly concerned with my grades as long as they were passing.
The guy who graduated last in his class from medical school is still called "Doctor" and I have never had to show my grades to gain employment.
If you are struggling with the material, then study more, get with others and find out what your weaknesses are. There are dozens of threads on this subject so I will not recap them all here but the class is no different than any other class you have taken in your life. When you had trouble, what did you do to overcome it and learn the material or perform better on the exam?