While you might have practice for in-person exams, online exams are a bit different. So, you can try attempting a mock paper to train yourself, and boost your performance. For this, you may discuss it with your professor, if you can use the exam software for the task.
You may set exam conditions for yourself, and use your chosen study space to see if it suits you. Also, check that you should have an uninterrupted and swift internet connection as it will easily navigate the exam software.
Attempting a mock exam will improve your time management skills, and enable you to perform better. It will teach you how to attempt different types of questions, and how much time to allocate to each question. You may also learn the art of attempting the online exam, like you may skip a difficult question for time being, and return to attempt it. It will give you time to think about it, and reduce your errors.