Depending on the test, we will have different responses.
But in general, if you take an online test, you should prepare all the necessary learning materials for that subject, before it is obvious that you have to review the lesson carefully.
When taking the test, the formulas must be compared with each other in each work if it is English; must say the correct theorem, postulate and remember to check the answer if it is Math; As for Literature, it all depends on your reasoning ability. Remember if you have time, check the test again and don't think about too difficult questions, it's very time-consuming.
After submitting the assignment, never check your answers to see if you are right or wrong, because the work has been submitted, so nothing can be changed.
Note: if using a computer, remember to check the network connection, if using a phone, remember to charge.