1. The internet is more likely to have information on your family history the further back in time you go. 2. Trust in the accuracy is a consideration that you should keep in mind. Wikipedia is generally quite an accurate source.
http://www.genealogy.com/famousfolks/elvis-presley/index.htm#toc By scrolling to the bottom of this page you find that the information was prepared by Rhonda R. McClure (a professional genealogist) and posted on 16 January 2003.
Source citations give at least a small indication of credibility. Information with no citations at all may be accurate but it will take much more effort to verify.
The date a search was conducted is important, especially for online sources that may be updated periodically.
There must be enough information that another person can easily find the same information.
Record positive and negative search results.
Record positive and negative search results.
Every answer reveals additional questions. That makes family history research an enjoyable journey.