Performing the best searches depends on finding the best search terms. Notice hyperlinked keywords and subject terms in your results sets. Following those links or re-using those terms are ways to find more resources on a topic. When searching for books, Library of Congress (LC) subject terms can be helpful. The APA provides a list of urban planning related subject terms for use when searching for books.
Identifying your issue is a crucially important part of your project. Search broadly, but think locally because you'll need to apply broad concepts to specific situations. For ideas, browse through the planning literature on your class CTools site, read newspapers, and news journals. Think of issues that interest you or relate to your own life (public transport, affordable housing, crime and public safety, pubic services or public rights... ). On this page you'll find a list of blogs about urban issues where you'll find lots of ideas and discussions. Remember that while blogs offer a fantastic view into an issue, a blog can be used to express strident opinions, so check the author and the source as you evaluate the arguments presented.