Within pretty much every photo is EXIF data, or an account of practically every setting on the camera at the time the photo was taken (and more). If you're just learning the basics of photography, one way to improve your skills is to study the work of professionals.
As how-to tech blog How-To Geek points out, thanks to EXIF data you can often find out every last detail of what they're doing.
If you find a photo you like and want to study it, try to find an original copy and download it. Often times you can find originals on photo sites. Flickr, for example, allows users to provide access to the originals via the Actions menu. Just choose "All Sizes" and click the largest size. This should provide you with the original photograph.
Once you've got an original, you can use several applications to read the data. If you have Adobe Photoshop, Lightroom or Bridge, you can use those to read the EXIF data. In Mac OS X, you can also open the photo in Preview and choose "Show Inspector" (Command+I). In Windows 7, just right click the photo, choose "Properties", and click the "Details" tab.
With the EXIF data in front of you, you'll be able to see what kind of lens was used (and its focal length), the chosen shutter speed, ISO and aperture, the type of camera that took the picture, and a whole lot more. You can then recreate this combination of settings on your own camera and try to take a similar photo. Obviously the light, your subject, and the composition you choose will play a large role in how the photo turns out, but learning from EXIF data can take away the mystery of the technical details you also need to know.
How to Use EXIF Data to Learn From Master Photographers [How-To Geek]