NineFireStar has really good advice! But also, while I respect your desire to get into this course, it doesn't really decide your future. There are so so so so many ways to get to the same destination, and while you should absolutely try your best don't be devastated if you fail because there are so many options open to you and maybe it's a sign that that course just wasn't the right one for you. BUT GOOD LUCK ANYWAY!!!
I agree to some extent, many positions you can reach through a multitude of ways, but those that are most rare are not as easy. Also, don't underestimate the value of the time lost on trying again, it could cost years, so better to really go for what you want at once with the full dedication that you have for whatever it is.
1. Make sure that you remember whatever you're studying, that means repetition as well as good sleep 2. Make sure to come to the test well-rested, nourished and with clarity of mind, that means continous exercise and not over-exerting yourself right the days before 3. Studies have shown that you are more likely to remember things in the same setting that a memory was created, so if it's at all possible, try to study in the same room that you're taking the test 4. Don't waste time on fear/worry, this is a matter of preparation. If you do your best, you'll be less apprehensive and also be able to say that you did. 5. Study with others, they'll fill in the gaps you have, also you'll see different perspectives on the same thing and learn by explaining things to others.