Whatever you are looking for, iDiscover is always the best place to start. As well as finding print books and where they are located, it is also your gateway to ebooks, ejournals and articles.
Sometimes you might find you get a lot of results without anything immediately relevant standing out. This is where the "Refine my results" section on the right of your results comes in handy.
Try a search using fewer words, select the most relevant keywords, also, don't forget about synonyms or related terms.
For more information about searching, you could look at the Camguides section on "Searching effectively".