Photographers often remark that digital cameras capture photos that are a little "soft," and it's true that most digital photos can benefit from judicious sharpening. If you shoot in JPEG format, your camera is probably adds a little sharpening automatically. If you don't think it's enough, you can add some more in your photo editor. If you're shooting in RAW, of course, the only sharpening will be what you apply yourself.
The most common way to sharpen a photo is by using your photo editor's Unsharp Mask tool, which you control by varying three controls, usually called Amount, Radius, and Threshold. As you make Amount and Radius larger, the sharpening effect increases, so check the effect when viewing the photo at 100 percent magnification and be careful that you don't overdo it.