I took my practical exam just last month, and like you, was extremely nervous. I have a bit of test anxiety in general, but with practical exams it's worse. I don't like being put in any sort of spotlight, so having to get up and talk in front of people makes me extremely nervous, (actually it scares the living :censored: out of me!). However, I passed the practical without any re-takes.
My advice would be to practice, practice, practice, and practice some more. I did pt assessments on literally everyone I know. The best thing to do is practice with someone who knows what you're doing, and knows the criteria. An instructor from your class or another EMT. Practicing with other students is good, but practicing with someone who really knows the material is better, like an instructor or someone who has been an evaluator in the past and knows the new criteria, (make sure they know it, one of my instructors in class wasn't up to date and was failing people left and right on the final class practical before the other instructor realized what was going on!). So, basically, practice until you're almost certain you can do a perfect assessment in your sleep, and then practice again!
Go to the testing place early. Give yourself time to relax a bit before you actually start your start your stations. I think being a bit familiar with the building you're in is actually helpful. You don't need to know where are all rooms for the stations are or anything, just get somewhat comfortable with your surroundings. It really helps to put your mind at ease. It might sound odd, but being in an unfamiliar place with unfamiliar people is stressful, even if you don't
feel stressed about it. At least it is for me. I was lucky to be able to test at my school, and the waiting area in between stations was the same classroom we had our EMT class in. Walking in, it felt just like another day of class. Which definitely calmed my nerves a ton!
When you go to your stations, take your time. Don't just walk in and start right away. I know they tell to you look at all your equipment and everything, and since you already know what equipment you have, it seems like a waste of time. It isn't. Even if you don't really look at or check everything, just make sure you know where it is and use that extra time to simply calm your nerves. I think there were a few times I walked in and dug around in an ambulance bag, not really looking at anything. I looked busy, I'm sure, but really I was just standing there trying to breathe! Also, having a good attitude goes a long way. When you're checking the equipment or just getting your bearings before starting, chat with the evaluators. They aren't mean, nasty people out to fail you or anything (well, most of them anyway!). Don't spend all day asking them their life history or anything, just say hello, ask questions if you need to, even state that you're a bit nervous. They've been through this and they know exactly how you feel, so they're usually very kind and sometimes even a bit chatty. Which is good. They aren't going to give you good marks just for being nice and talking with them, of course. The idea is just to get somewhat comfortable with the people in the room. You're not in a room with a bunch of total strangers there to judge you. You're in a room with new acquaintances and maybe even future co-workers and friends.
When you start, (and don't forget BSI!), just take your time. Don't worry about the clock ticking away. You have plenty of time to get everything done. I am terrible when it comes to time limits. I always mess up if I'm being timed, because the stop watch is all I can focus on. When I took the exam, I just pretended the evaluators weren't even there. I focused on my pt and what I was doing and tuned everything else out. Be confident in yourself. If you focus on everything that you will do wrong or did wrong the first time, you're more likely to make mistakes. Focus on what you need to do and nothing else.
Don't forget about the EMTs that are there to help you and act as your partner. I think I had at least one in every station, except the med and trauma assessments. If you need a minute to just stop and think, and you have a partner who isn't doing anything, direct them to take over. I did this in the AED station, simply because I got distracted and forgot what my next step was. I asked one partner to take over ventilations while they other did compressions and just sat back and tried to remember what I supposed to do. It helped, for sure. In all the rush of things, (that station felt really rushed and very realistic for me, despite the pt being a mannequin), I just needed to take a quick minute and breathe. After that I flew through the rest of it.
Also, don't forget that you can talk to your patient and the evaluators. If you forget something, ask someone. Don't worry about sounding stupid for asking what the patients blood pressure was, even though they just told you ten seconds ago. They know you're nervous and that you're going to forget things that in a calmer situation you'd easily remember. You said you are more comfortable with written exams and book work, so writing stuff down may be helpful for you. If you have trouble remembering where you're at in an assessment, it might be helpful to sort of check things off as you go through it. You just checked the ABC's? Write down ABC. Then, if you get a bit lost at some point, you can look at your notepad and see what you just did. Sometimes that's all you need to refresh your memory on what the next step is. It's good if you're someone who tends to forget the steps. You can look at your list and realize that you didn't listen to lung sounds or whatever. If you realize you missed something, make it known. Listen to those lung sounds or at least verbalize that you would have. It might be a bit late, but you might still get the points for doing it. I nearly missed a critical (automatic failure) on my trauma assessment. I jumped right over "transport/pt priority" and started my rapid scan. I was at the guy's head when I realized this, because he stated that his head hurt when I touched it, and I turned to the evaluator and told him that it was a priority patient and I would transport immediately after the initial rapid assessment. I still passed. If I had gotten down to the chest and then realized this, I probably would've failed it.
The most important thing, I think, out of all of that stuff I just said, is to remain calm. Since you had such high scores in class and passed the written, you obviously know the material, so it's probably just nerves. Just remember the critical criteria. If you walk out of a station and realize that you forgot something minor, don't stress about it, because you're not going to fail. Just don't stress. After each station, forget about it. Don't start thinking about what you missed and every little mistake you might have made, because you'll just walk into your next station thinking about that instead of what you need to do in the new station. What's done is done. If you have to retake a station, it's not a big deal. Don't psych yourself out stressing over it. I was 100 percent certain that I failed a station, only to have passed it. Just focus on the present task, not the past ones or the future ones. And never, ever think about the time. As long as you get all the critical stuff and vitals in on time, even if you don't finish everything else on time, you will most likely pass. Someone in my class went over the time limit for the trauma assessment, and still passed, simply because he got all of the major stuff, critical criteria, and vitals done within the ten minutes.
Wow. This reply is getting a bit long. Sorry about that. I hope my advice and trip down memory lane has helped you! I wish you the best of luck on your exam. Let us know how it goes!
Also, one more thing: I don't know if you can do this, but when I took my practical, we were allowed to look over our papers (with all the steps and criteria) before every station, we just could not take it in the room and obviously couldn't use it during. That helped a ton. Remembering all that information and all the steps is difficult, especially when you're nervous. Perhaps you should take the sheets with you when you test and ask if you can look them over in between stations.