Face should be done on skin maker... unless ofcourse you are using non-HD, it will be difficult for beginners. just turn on Smooth which is located on top right corner. and make the invisibility lower (also known as A on the color side). only time you should use photoshop/paint is to get the colors of the character you are creating. the face is easier to make in skin maker but i recommend doing body in photoshop since it can easily add contrast.
watch this to get the basic idea... and remember!!! YOU NEVER EVER!!! EVER EVER EVER!!! COPY AND PASTE SMALL PICTURES INTO YOUR SKINS!!!!!!!!!!!!!!!!!!!!!!! hate it when people do that =.= (excluding hatak skins ofcourse)
Good luck =p