Good luck with your coming test!
May I give some suggestions? If they're not relevant to you, just forget about them.
Often in a shodan test, you are expected to show a decent ability with the basic techniques in the basic attack forms. Beforehand, check through the list of demands for the grade, and try out the things you have not done in a while. It is easy to forget how to do a basic technique against one or other uncommon attack form, especially in the stress of a grading test.
At the test, make sure to do reigi
(the bowing and stuff) with style and devotion - that will make the examinators positive, and the opposite might aggravate them.
Along that line: make sure not to let uke pay for your shortcomings - for example by using unnecessary force when you are unsure of how to manage a technique.
If you lose your breath - and that is likely in a test, where the nerves make you waste a lot of energy - concentrate on exhaling forcefully, so that you give room for fresh air to enter your lungs. Don't worry about inhaling - your body will take care of that fine, without you having to think about it
At the moment when you enter into a technique, start thinking about what you might need to do after it is finished. This is a good way to stay ahead, so to speak. Many people tend to think only about what they are doing at the moment, so they have no time to prepare for what they need to do next.
When you have entered a technique - the first step and arm movement - you can trust that the body knows how to finish it, without your mind needing to focus on it.
Try to keep a straight posture throughout. That makes the techniques look fine, even if you don't do them perfectly
There's more, but that was what I got off the top of my head. I hope it is of some use to you.