Did you know that the Library module in Lightroom has the ability to Auto Sync? I find this especially useful when using Survey mode. Let’s say, for example, I start with 10 similar images and then remove the less important ones until I only have 4 left. If I want to flag, rate or label all four of those images at one time, without leaving Survey mode, I just flip on the Auto Sync switch. Then, whatever I do to one, is done to all.
Just don’t forget to flip off Auto Sync when you are finished.