Details please.
If not, standard most used is UnSharp Mask in the filters. Warning, out of focus is out of focus, your definition of "blur" can tell us whether what you’re asking is impossible, or help someone give you more explicit directions.
My favorite way to sharpen remains a Hi Pass sharpen, although it won’t work miracles:
1. Duplicate your image layer
2. Apply Filter > Other > Hi Pass after first adjusting the Radius slider to raise some of the details, but not too much (practice with various settings and learn what works for you). The higher the image resolution, the higher the radius you can use.
3. Change the blending mode for the layer to Soft Light, Hard Light, or Vivid Light, again the choice being developed over time and perhaps varying according to the image. I often use Hard Light
4. Reduce the Opacity of the layer to reduce the degree of "sharpening" produced by the layer. I find 30-40% usually works well for me.
5. Save the result in PSD or layered TIFF format so that the sharpening layer can be easily discarded or changed in the future.
Hope that helps,
Daryl
