I read and learnt a very useful technique yesterday.
It is for smoothing skin (especially for faces) in PS.
I have a Samsung camera which detects faces when focusing and auto-smooths them when I shoot. However, my iphone's camera application does not do that automatically.
I do have a few other applications that can do it but that will mean switching applications during photo-taking.
So I decide to do some googling and found a useful tutorial here.
If you are interested, read it up!
Here's my result.
Steps are very easy:-
1. duplicate a layer
2. create a quick-mask on the new layer and paint over the area you wish to smooth
3. go back to standard mode and feather selection (or feather the inverse)
4. add a filter of gussian blur (radius approximately 3 pixel) to the painted area
5. add a little bit of noise (2.5%) so that it is not overly smooth