Guys, any tips for drawing realistic faces?

I can draw anime style faces, but I failed miserably at realistic faces. I been trying to draw my friend for ages, but I just can't seem make it resemble the person or realistic enough. Facing troubles especially at the eye and mouth and the overall shading I should use.

I need to reach a level where other people can see the picture and recognize the person I am drawing.

My skill levels is lower than the quoted Adamiquesce picture above.

I look at some tutorials, but none seem to help me at drawing better.

More info - I draw with purely pencil and paper, I don't use photoshop or anything to touch up.

This post has been edited by kalandra: Nov 9 2014, 12:50 PM

I think I am still getting the primary sketch wrong. And my tones is still very bad.

Do you mind if I PM you my sketch and the photo I am trying to sketch?