In a fair test you make an observation, this gives rise to a question and you make an explanation called the hypothesis, you test the hypothesis with an experiment, analyse your results and then see whether it agrees with your hypothesis. If it does agree with your hypothesis you now have evidence that your hypothesis is correct. If it doesn't agree with your hypothesis then you have to go back to the drawing board and make a better hypothesis.
Well done, you know all about fair testing!
If you didn't get everything correct:A few mistakes, why not try again!