Sharpening photos taken at higher ISOs is a tricky thing, as you run the risk of making the appearance of noise much worse very quickly. This helpful video will show you how to sharpen high-ISO photos to enhance detail while still reducing noise.
Coming to you from Blake Rudis at f64 Academy, this video will show you the ins and outs of sharpening high-ISO photos in Photoshop (or Lightroom) while reducing noise. High-ISO files tend to have much less latitude, so it's important to be very precise in your edits. As Rudis shows, noise reduction and sharpening are interdependent, and you can't consider one without also taking into account the other. The biggest takeaway, I think, however, is that it's less about the amount of sharpening you apply (though that of course still matters) and more about masking it in carefully so areas of nuance show more refinement, while broad, uniform sections of the image (where noise is more immediately apparent and sharpening isn't needed) are left untouched, making the noise reduction more effective and resulting in a better overall photo. If you're someone who spends a lot of time in less-than-ideal lighting conditions (like a wedding photographer), really dialing in this skill will help you improve the overall quality of your output.