One mantra that most designers and Adobe Photoshop gurus follow is to NEVER use the Sharpen, Sharpen More, or Sharpen Edges filters in Adobe Photoshop. That leaves just one (often misunderstood) filter for all your sharpening needs: Unsharp Mask

Confusing name, but Unsharp Mask gives better results. A great tutorial on sharpening images by dvGarage's Alex Lindsay is available at Tech TV's Call for Help website. (For more Photoshop tips and tutorials, Alex appears every Wednesday on the Call for Help website and TV show laying out Photoshop tips for both beginners and the pros.)