It is a learning process based on critical thinking. The basic steps follow. Not every scientist applies them in just this way every day. Actually, anyone who thinks critically or uses logic in his or her life probably applies a variation of this method in problem solving. If your results are not as expected, check for other factors or re-examine your hypothesis.
Hypotheses supported by multiple tests are stronger.
A scientific theory is a set of related hypotheses that, taken together, form a broad-ranging, testable explanation about some fundamental aspect or phenomenon of the natural world. But, relative certainty is sometimes very impressive. Many theories withstand vigorous, extensive testing. They may be added to or modified but are not likely to be disproved. Scientists are people Scientists strive to discover objective explanations about the real world.