Searching the WWW and other subscribed databases for relevant information requires certain type of expertise. The kind of expertise needed may vary from one search engine to other however; following preliminary searching hints will definitely be of good help.
Choose a search engine, Database, directory or library in accordance with the kind of search you are doing and the kind of results you are seeking.
Consider: What exactly you are looking for? General information that might be available in public domain or Academic articles that might be available in public domain as well as in subscribed databases.
Determine your aims: Do you want a specific hard-to-find document on an esoteric subject, or general information on a broader topic? Do you need to search the entire Web, or is what you are seeking likely to be found on a number of sites, or only the most popular sites?
In making your choice, determine whether the information you are looking for is likely to be in a page's title or first paragraph, or buried deeper within the document or site. These you may be likely to define while making advance search in subscribed databases.
Use a search engine's advanced features, if available, and read the help files if you are unclear about its searching procedure.