Just as a warning, I'm no pro at realism, but I'll try my best to convey the basics of what makes a realism portrait realistic and 3 dimensional.
PROPORTIONS; this isn't so tough. Eyes are naturally positioned in the middle of the head (yours were
very close, though!). The bottom of the nose meets with the bottom of the earlobe, also our eyebrows meet with the top of our ears (I've put two horizontal lines depicting this). The bottom of the nose is positioned at around 1/3 of the face, from the bottom of the chin. I don't remember about the mouth, though... aslkfnalks My bad D:
Both eyes are separated an 'eye' length. It helps to draw an actual eye in the middle of the nose bridge to position the eyes.
Also, women cheeks tend to be less curvy on its side because of the fat. Men faces, however, have their cheeks super defined on the sides because they have less fat and more bone definition. Go figure.
3D VALUES;
this is the creme of the crop. This depicts whether your realism portrait is 3 dimensional or 2D, aka flat or non-realistic. Strengthen your shadows, strengthen your highlights. If you play too much with your 'gray' or 'medium tone' values, then the depth will be ultimately lost. Try looking at your picture at a distance. Can you see, not
believe, where the bottom ridge of that nose is? Can you see where both ends of the mouth are? Can you really see the 'mood' or the portrait? If it's blurry, retouch your shadows and highlights.
TEXTURE; This one's the icing on the cake, which means that you should not do it until your proportions and values are as accurate as they can be. It's like putting icing on your cake before it has been baked. Not much sense, thar. A general tip is to soften your shadows and sharpen your highlights. That's it, really. Not too complicated. o_o But the average artist likes to put those 'finishing touches' before they can remotely finish their under drawing, which is the downfall of many. When you put a highlight on the eye and go "Oooo that's so pretty" but then you need to redraw that eye due to anatomical errors, you're less likely to do that because you don't want to sacrifice the "ooo pretty highlight". This is why. OTL
AAAAAH I should've written a book, instead. OTL