WordPress make it easy to upload and edit your photos and other media, but it can be hard to organize your photos. If you select “Organize my uploads into month- and year-based folders” in the Media section of Settings, you can search by date or phrase. But if you were silly and forgot to name your photos…well, you can have a hard time wading through them, if the date you uploaded them is not helpful, and especially if there is a lot of them.
Cohhe.com lists a few of the popular plug-ins to help you bring order to your WP media library. I have not yet tried the pay plug-ins, but I did try Enhanced Media Library plugin by webbistro and it didn’t really work for me. YMMV, of course, and it does have a lot of great reviews. People have bitterly complained that WordPress should have natively better way to organize media, preferably a way to create folders.
But if you prefer not to have to rely on a plug-in, a simple solution is of course to give a useful title for each photo or video. You can sort by date uploaded, and search by whatever term you choose. This is a good plan to follow no matter what plug-in you choose or what improvements WP might roll out down the road.