Tip 1: Gauge your time
Unless it's a take home test, you only have so much time to get it done. Look at the mark's for each question. Figure out the time to give each answer.
Tip 2: Know the rules
Ask your teacher about the rules for the test. Can you use calculator? Bring notes? Talk to friend? Do you get penalized for wrong answer? Are you better of guessing or leaving a blank?
Tip 3: Plan your attack
Often it's to take a minute or two to think about HOW you're going to answer the question.
Tip 4: Fill the space
If there are five lines for an answer, or a big space on the sheet, fill the lines or the space. They give you an idea how big an answer your teacher expects.
Tip 5: Check your answer
In math, work backwards to make sure your is right. Language arts, proofread to make sure your spelling and punctuation are correct.