Ask a question. The scientific method starts because of the question of something you observed that you need answered. Make sure that when you ask the question, you ask how, when, who, which, why or where. The question also needs to be answered with a measurement.
Research information about the question you are asking. You need to find everything you can about the question you are asking. This information must be scientifically proven, and also look for similar experiments so you don't make the same mistakes.
Make a hypothesis. A hypothesis is an educated guess of what you think the end result of your experiment will be.
Start testing your experiment. This will determine if your hypothesis is true. You must have a controlled experiment with at least two groups. In the controlled experiment, everything is identical to the other group except the one aspect you are testing. In the other group, nothing is altered and everything is natural. For example, if your question is, "Does sunlight affect the growth of a lima bean?" and your hypothesis is, "I believe that lack of sunlight will not allow the lima bean to grow," you will have two groups in your experiment, one with light and the other without light.
Finish the science project by observing what happened in your experiment after everything was tested. In the conclusion, you will see whether or not your hypothesis was right or wrong, and you can see what affected the answer to your question.