Outside of database searching, there is a significant ammount of research to be undertaken. The primary methods are listed below.
Hand search key journals
Forward citation search [some databases will allow you to identity articles which have subsequently cited an article you are looking at]
Review reference lists at the end of relevant articles
This is a useful way further related papers, similar to forward citation searching but looking to articles published previous to the article you are reading
General search engine e.g. Google or Google Scholar
There are a variety of search engine available, one of the most popular being Google. It is useful to note that you can export from Google Scholar to bibliographic referencing software.
Current awareness services
These might include
Consider research forums for gathering information and ideas on your field.