Descriptive keywords can help you organize your iPhoto library better. They only take a second to do, and they will save you lots of time when you want to search for a photo. Here is how to do it: Open iPhoto. Then from the iPhoto menu, choose 'Preferences'. Next, choose 'Keywords'. Now you can add your own descriptive keywords. Just hit the '+' to add a keyword, or '-' to remove one. The more descriptive you are, the easier it will be to find a particular photo. You can use combos too -- add a keyword for 'Vacation', and perhaps one for 'Washington'.. then you can tag the photo with 'Vacation' and 'Washington', which will be separate from your vacation in 'London'. Or you could simply search for 'Vacation' and it will bring all of your pictures with that tag. Next, bring up the keyword panel (so you can see the list of keywords you created), and then select some photos to tag. Then drag and drop the photos onto a specific keyword. You can add multiple keywords, so simply repeat the process. Notice in my photos, I have a keyword 'Family', and a keyword 'Vacation'. Now that you have some tagged photos, click on the 'Library' in the source pane (left side of iPhoto) so it will search all of your photos. Then in the search box, type in one of your keywords, and test it out. If you want to search without iPhoto being open, simply use 'Spotlight' to search for your photos.