put in the hours use all the resources do thousands of questions take the nbme exams and get a 250 on step II. even with that you have things that are going to go against you when you are looking at allopathic anesthesia spots. apply far and wide and nail the interview and dont ever say you are a bad test taker, instead tell people you had a bad day and came back strong etc.
"bad test taker" is a character flaw in many peoples eyes and wont endear you to a program that has the desire to have their residents perform well on in training exams.