Begin by thinking of several ways to accomplish this. Base these possibilities on past observations. If you put each of these possibilities into sentence form, using the words if and then, you can form a hypothesis. If I am intelligent, then I will get a perfect score. If I study hard, then I will get a perfect score.
Scientists make hypotheses that they can test to explain the observations they have made.
Perhaps a scientist has observed that plants that receive fertilizer grow taller than plants that do not. Once you state a hypothesis, you probably want to find out whether or not it explains an event or an observation. This requires a test. A hypothesis must be something you can test. To test a hypothesis, you design and carry out an experiment.