Clarity slider in ACR works using the adjustment brush. Personally, I prefer the surface blur tool over the gaussian blur tool. I just convert layer to a smart object, adjust until the skin looks decent, paying no mind to the rest of the shot. Then I fill a layer mask with black, and paint in using white on the skin to apply the blur. Prior to this step, I remove blemishes on dupe layer using the patch tool or the healing brush tool. This I do seperate so opacity of blur and blemishes can be adjusted independently. If someone has a prominant mole for instance that is unflattering, you can simply reduce the opacity so that its still there, but less attention grabbing. That way the client doesnt feel like you made them look unlike themselves, but they still look more flattering than they have probably ever seen themselves.
