I didn't really appreciate the importance of having an efficient and consistent Lightroom workflow until I started shooting sports and events and coming home with thousands of images from a shoot. If you're in the same boat as I was, this great video will show you an efficient way to work with large sets of images.
Coming to you from Tyler Stalman, this helpful tutorial follows him as he culls and edits a large set of photos from a wedding in Croatia. Besides simply being efficient so you're not spending all your time editing photos, developing such a workflow is important as it ensures your edits are consistent across the entire collection that you deliver to your client. It can be easy as you move from image to image to inadvertently edit them slightly differently, particularly if you break up your editing into multiple sessions across days, as you often have to with larger sets. While each individual photo's edit may look good, if things like color and contrast shift too much across the set, it can really lower the overall perception of quality. As Stalman mentions, it's important to constantly check the overall collection of images to ensure they all have the same overall style and look.