ADDING IN YOUR CLOTHING
CHOOSE THE CLOTHES
Hide the layers that are in the way of you seeing your clothing. Put the clothing layer above all the layers except features. If you want to be wearing different clothes, find a good reference on google and work from that.
Work The Same Way As The Face:
First, find the edges of the clothing and put the base colors on them.
Second, lower the opacity of the base shapes and start adding in the highlights onto the clothes and change the color to a lighter color.
Lastly, add in all the shadows and small details. I make sure that the clothes work together with the face by unhiding the face layers and hiding them again for changes. Here, I changed the base color of my outer jacket so I can add in shadows.
CHECK YOUR PROGRESS
After this step, you should be pretty much done with the foreground. So, unhide the face layers and hide the reference photo and look at your work as a whole to check for any mistakes in any layer. Also, remember to save your work (⌘S)!