One good site will lead to other sites relevant to your topic. Most search tools allow only one search statement. Use the most unique or unusual word for your topic or use a search engine that allows you to specify what part of the index to search in. Each search tool provides instructions for its use. Even if you are familiar with a particular search tool, read the help and FAQ for that tool on a regular basis.
Search features change constantly.
Be sure you understand how the search features work in the search tool you are using. Watch for new developments and new search tools. Some of the currently available search tools are briefly described below. A link to each tool is also provided. Many other sites provide links to a variety of search tools.