One of the most fundamental steps in genealogy is to keep track of where you got your information. At first it can be exciting to gather names, dates, and places. In your excitement, also write a complete citation for where that information came from.
I love the book that Elizabeth Shown Mills wrote about sources called Evidence Explained. In it she discusses numerous types of sources that a genealogist would encounter and how to write a complete citation for each. She even has a website with additional information at www.evidenceexplained.com . I have referred to the book many times, particularly when I was citing a wide variety of sources in the NGS Home Study Course assignments.
A citation will help you sort through your evidence. We are all bound to come up against conflicting information at some point, and the source helps us weigh which to accept. It will also show other people that they can believe your information, and will help them weigh their evidence against yours.