certain textures are easi to accomplish
probably not much different in photoshop, but in paintshop - you take what you want to make plastic and firstly point-to-point select saving the selection to the alpha channel then outline it with a point-to-point white line (1pixel)
add outlines where the plastic lines are to be with another few point to point lines, i'd start with one and check out how it looks and move on. Increaseing the size because it should be slightly larger, then duplicate that vector layer making all the lines in the layer down about 1/4 the size.
Hide the top layer and then using selection, select the entire screen and the select float - finally defloat to get the selection area ... or you could use the layer panel and select each line as raster selections, but when i do that i tend to accidentially promote to raster level hehee
Now feather out the selection by about 2pixels but change to look right. Gausian Blur 10.0 ... now without changing the selection unhide the top layer and gausian blur at 4.0
(not looking too plastically
but just wait)
Now you remember that selection alpha you made earlier?
Use that to select on the original picture and duplicate it hiding the original. Combine the visible layers and then goto texture -> soft plastic ... using Custom5 is a good one, then unhide your original picture and change the plastic layer to lumination.
offers a very nice effect, just go over the actual effect with a few light airbrush black strokes to add some darkness is a good effect.
probably almost identical to achieve within photo (^_^)
Anata aru kowagaru no watashi! 
