Have you ever wondered why other people’s photos and layouts look so much crisper than yours? They have probably figured out the secret to using the unsharp mask command in their editing program. In order to make sharpening your photos work for you, it’s best if you understand WHY your digital photos need sharpened. Almost all digital point-and-shoot and SLR cameras contain an optical filter in front of the image sensor called a low-pass filter. It improves overall image quality, but in the process blurs image detail slightly.
Photoshop’s Unsharp Mask filter allows you to adjust three different factors when you sharpen: Amount, Radius, and Threshold. The amount setting adds edge contrast to detail that’s already in your photo, adding contrast to light/dark transitions. The higher the value, the greater the contrast. The radius setting determines how many pixels out from an edge will be affected by the amount setting. The higher the radius value, the greater the width of the affected area. If your photos have ever looked “too sharp” or you’ve noticed a halo around the edges in your photo, you probably need to bump this setting down. The threshold setting how different in tone adjacent pixels have to be before they’re considered a light-dark transition to be sharpened. The lower the threshold value, the greater the number of pixels that will be sharpened throughout the photo. (info from www.microsoft.com)
Here’s my photo before:
Navigate to the unsharp mask: filter>sharpen>unsharp mask
Enter your unsharp mask settings. A fairly common combination is Amount: 20%, Radius: 60, Threshold: 0. Another common combination is Amount: 85%, Radius: 1, Threshold: 4. Remember, there is no magic number that is going to be perfect for all of your photos. Don’t be afraid to play around with the settings until you are comfortable with the way your photo looks.
Here is my photo after sharpening. The effect is subtle but definitely noticeable.
Have fun, play around, and look SHARP! 
