Awareness of the indexing policies of a database, and use of its thesaurus, can add greatly to the power of a search, especially in situations where initial attempts have not resulted in much relevant information being found. The choice of database is important. There can be significant variations between databases in their coverage of a topic, and also in the way in which it is indexed. While a search in a single database can be sufficient if only an indicative result is required, performance of an exhaustive search will require a number of databases to be used. A number of different types of databases will be briefly described.

The success of a search is influenced by a number of factors, which will be discussed. In the case of Internet searches, the choice of search engine can be crucial. Some tips for using search engines will be given. However, there is also information available on the Internet that cannot be found using a search engine. Resources which provide access to this 'Invisible Web' will be discussed. Finally, some web sites specifically relevant to the 3Rs will be described.