If you're looking to expose some detail on any of your photos and have Photoshop, check out these easy tips. I've been using the first one, unmask sharpen, for a long time, but more recently with some stuff at work and it makes a huge difference. It seems to add fine detail to images and lessen the appearance of blurryness. Open up an image in Photoshop and navigate to Filter » Sharpen » Unsharp Mask. In the window that pops up, set the amount to 100%, radius to 0.5 pixels and keep the threshold at 0 levels. Click OK. That's it! I've found that this works particularly better on some photos than others; non-macro shots seem to fare better.
Original
This is a part of Georgia Tech's West Campus. In the background is the world's largest (or so we're told to believe) astroturf field.
After 1 Unsharp Mask Application
Notice how the people in the back are more defined as are individual blades of grass.
After 2 Unsharp Mask Applications
Finding the right balance is key. Go too far and you'll wash out the colors. For example, the grass here isn't as green as the photo above it.
I wouldn't recommend using more than 1 or 2 unsharp masks as it can start to deteriorate the quality of the photo. Another powerful photo enhancement can be done with the High Pass filter. Open up a new image, duplicate the image layer and go to Filter » Other » High Pass. Select a Radius from somewhere between 5 and 10 pixels; play with them and see what looks best on your particular photo. Hit OK. The layer will look a little weird right now, that's normal.
If you go to your layers window, you should have 2 layers - the untouched original and the duplicate which we applied the filter to. On the filtered layer you were just working on, right-click and select Blending Options. In the main window under General Blending, set the blend mode to Overlay. Click OK and you're done.
Before High Pass
After High Pass
Learn to mix these two filter techniques together and you can easily turn a mediocre photo into a masterpiece worthy of your flickr account.
While we're on the subject of Photoshop, Bryan created an excellent screencast tutorial of clipping masks in Photoshop. It's a decent 50MB download but has many tips that the Photoshop newcomer will find essential.