- Form a general idea of what it is that you want to paint, and I emphasize the word "General", just think of the broad concept/theme or the subject of your painting and don't get into the little specifics, those details will work themselves out as the painting goes along.
- Divide the painting into little sections, and work on them (till near-perfection) separately; one section at a time, and don't move on to the next part until you have completed at least 85%-90% of the part you're working on at the time, for example; if you're doing a human portrait; start working on one of the eyes; once you've finished it completely (or 85%-90% of it) move on to the other eye, after that the nose
- In the process of drawing/painting each part; pay serious attention to the slightest of details 'cause that will bring your work to life, and through these details you can convey the emotions that you would want people to get when they look at the finished painting, now these little details might not even be noticeable at a passing glance but they will sure contribute to the overall sense of realism of your work.
- Start painting from left to right (your left to your right; and in case of a human portrait, it would be the portrait's right to left) and from top to bottom, that's very important so that you don't accidentally rely with your elbow/arm/hand while working on a part you already finished, that would leave smudges and it could very well ruin your painting (charcoal and graphite work are really sensitive)
- Shades of Grey (Shading); when it comes to charcoal and pencil work, I can't emphasize enough the importance of this concept: Shades of Grey, should represent to you what colors represent to acrylic and oil painters, the "lack of colors" in charcoal paintings can very well be compensated for by efficiently utilizing different shades of grey, your painting should not be solely black and white, you should use all shades between these two major contrasting colors to give your painting a sense of realism, and that can be achieved through various methods such as: pressure, cross-hatching, blending, using different ranges of wooden pencils (8H-8B)... etc.
- Pressure: whether you're using charcoal, graphite or pencils; the different amounts of pressure you apply on the painting will eventually yield different shades of grey, for example: if you pressed the pencil hard against the paper you will probably get the darkest tone of that pencil, whereas if you held the pencil lightly against the paper you'll get the brightest tone from it, and to fully get the hang of this, you can exercise by using anything around you (pens, pencils, charcoal
etc.) and start applying gradual pressure on the paper to notice the different shades of grey that you'll get.
- Cross Hatching: this is done by drawing straight lines closely adjacent to each other; and then drawing over them other straight lines in opposition to their original direction; placed to create an angle with the previous lines (I don't know if I'm conveying this thought well enough but its basically drawing in a sideways manner and then drawing over that in a crossways manner), the closer the lines to each other, the darker the tone you will get, personally I actually hate this technique and I rarely (if ever) use it, as I feel that it gives the painting a caricature-esque impression.
- Blending: this method is essential for achieving realism in your work; graphite/charcoal lines must be subtle, barely noticeable for the naked eye; the beauty of the human portrait lies in the subtlety and the delicacy of the work. Blending can be achieved by utilizing tissues (regular Kleenex), but personally I prefer using white cottons & tortillions (paper sticks), and although many professional artists advise against it; oftentimes I just blend with my fingers.
- Try to make your painting as realistic as possible but without trying to come off "too realistic" because that will backfire on you, you have to know when to stop; once you think you have reached a reasonable/acceptable level of realism don't go any further, make sure that whenever people see the painting; they'd recognize that its in fact a charcoal painting and not a B&W photography.
- When you do a portrait; don't draw the person. draw his/her personality