Sharpening is a serious issue, there are a lot of things to be said about it. However, for now, we'll stick with the practical sides of it.
To sharpen your photo do the following:
- Open photo in photoshop.
- Select filters -> Sharpen -> Unsharpen Mask.
- Values: Well it depends on how much sharpening would you like to achieve (yes, there is such thing as over sharpening and it can ruin your photo too!).
Amount: The amount of the filter to apply, the higher the more sharpened the image will be.
Radius: The filter is applied in a radial manner, therefore the larger the radius the bigger effect of the sharpening.
Threshold: Is the amount of differences between colors that control when this filter is applied, the higher value the less pronounced the effect will be. - Click the preview button to see the photo with and without the filter until you decide you like the outcome.
And voila! There you have a sharpened photo.