Determine the question you want to answer with your conjecture. For example, assume you want a quick way to measure alternate angles formed by intersecting lines.
Create three hypothetical examples to measure. In the example, you would draw three pairs of intersecting lines.
Take all necessary measurements and record your results. In the example, you will find that opposite angles will always be equal, and adjacent angles formed will always be supplementary or add to 180 degrees.
Form your conjecture by using precise wording. The example is the Vertical Angles Conjecture: "Two vertical angles will have equal measurements."