A hypothesis is an educated guess, so what I think would be a good way to make a hypothesis is to research the topic a little bit, and make an assumption based on what you learned.
Like, say I'm interested in gases in balloons. I researched, and now I know that helium-filled balloons rise to the ceiling and balloons filled with regular air don't. I'm going to say, based on that, that helium is less dense than air which causes it to rise to the ceiling. I may or may not be right, but it doesn't matter right now. All that matters is that I can come up with an experiment to test my hypothesis! So my experiment would be testing if helium is actually less dense than air.
What Makes a Good Hypothesis? For a Good Hypothesis, You Should Answer "Yes" to Every Question Is the hypothesis based on information from reference materials about the topic? Yes / No Can at least one clear prediction be made from the hypothesis? Yes / No Are predictions resulting from the hypothesis testable in an experiment? Yes / No Does the prediction have both an independent variable (something you change) and a dependent variable (something you observe or measure)?
