It depends on how much time you have, but practice as much as you can, and, most importantly, make sure to stay calm.
Explanation:
When it comes to tests, the main thing which really helps is to practice answering as many questions about the topic(s) as possible. Since in your case it's a language, I would recommend, if you have time, making flashcards on the terms you have to learn, and also get someone to test you many times after memorising. The only way that you'll know if you're prepared is if you can answer questions confidently and you generally don't feel too worried. Since it's tomorrow, as long as you stay organised you'll be able to get in enough practice, trust me. What really helps for me is to put timers on for every section of the stuff I have to revise before a test, and making sure that I stick to each allocated time. Also, make sure when you're revising to take short breaks after every 30 mins or so to give your mind time to process the information. I would recommend a 5 minute break every 30 minutes, but it depends on the type of learner you are. Also, make sure to stay well hydrated and keep some water beside you on your desk if that's where you're revising. Another thing I would recommend is that, if you can, ask your teacher on email for example about anything you're not sure about so that you can understand fully before going into the test. The thing about revising is that you want to be checking boxes on things you understand, rather than learning something completely new.
