The scientific method has been used for centuries to test theories. It is quite simple in nature and requires a few simple steps. You come up with something you want to find out and research the topic. Next you will come up with a feasible idea or hypothesis about what you have researched. The next step is to experiment, or test what you have hypothesized. Once you complete your experiments you can crunch your numbers and results and determine if it is likely your hypothesis is correct. With your information in order you can present your facts in an organzied manner to convince others that your hypothesis is correct or incorrect.
Here is an example. I have observed my four cats over a period of two years. I have noticed they do not eat cat food in which the primary ingredient is turkey. My hypothesis is my cats do not like turkey. In order to test this hypothesis I will attempt to feed the cats various foods which contain turkey as the main ingredient. I may set out two bowls of food, one with turkey and one with some other flavor. I will then observe which bowl they eat from, and I would conduct this over a period of time and use different flavors to compete against the turkey. At the conclusion of the experiment I would note the number of times my cats ate the food which primarily contained turkey as opposed to the number of times they ate the other food. If the cats never ate the food which contained turkey as the primary ingredient, I might conclude my hypothesis is correct. However, I need to make sure that I have run sufficient trials and provided numerous options to feel confident that I am correct. If I simply test this once or twice, that may not be convincing evidence to most people. A hundred trials would be a lot more convincing.