Here are the steps I tend to take when sketching a portrait. I knocked up this example (thanks Steve, for letting me draw you!) in about an hour - it is still full of technical mistakes, for instance the left eye needs redoing completely and it looks as if he is looking sideways, but still, I think I have captured the general process!

I work in pencil for the initial stages, followed by charcoal then at the end I use a pencil again for fine lines.

If you look carefully at the photo above, you will see that I have drawn up guidelines over the original - I measure these up so that the guidelines in my sketch are roughly proportional.

Step 1: Setting Up Some Guidelines

On a black and white printout of the original pic, I drew up the following lines in pencil:

vertical: passing through the centre of each eye and one through the nose
horizontal: at the top of the head, bottom of the chin, through the centre of the eyes, at the bottom of the nose and through the mouth

I then drew the guidelines on my sketch according to the scale of the original, again, in pencil.

Step 2: Basic Features, and Rules?....what Rules?

Using pencil (any soft B or even HB will do), I lightly sketched in the main features according to the guidelines.

Now the 'rules' say that the eyes are halfway down the face, the nose is a quarter way up from the chin etc etc. Yes that's all very nice if your subject is facing dead centre, but even a subtle shift in perspective means you need to chuck out the rules and measure for yourself.

In this picture the subject's head is tilted up and back so that the vertical positioning of his nose, eyes etc do not follow the rules! See for yourself on the measurements I made on the original.

Once the basic features were placed using a pencil, I started shaping these features using charcoal.

As you can see, I prefer to capture light and dark areas rather than focus on lines.

Step 3: Shading to Add Detail

Starting from the eyes and working outwards, I keep adding charcoal to darker areas and smudge to graduate the shading using either a smudge stick or my fingers.

This picture is lacking in definition around the edges of the face and ears. The ears themselves have been defined in charcoal purely by a few small shadows, with no outline at all (any lines you see are from the original pencil work in step 1 and are erased later).

For teeth, I find that it is important not to view them as individual shapes with outlines - otherwise they end up looking like monster teeth! Instead I look for the small dark areas between the teeth and only shade those parts in.

Step 4: Smudge, Smudge, Smudge

I kept adding shading to define the eyes, brows and around the nose.

The lighting in the pic, and the fact that we are looking up at the face, means that we do not have a well-defined jawline, That is fine, stick to the shadows you see, not the ones that you expect and have faith that it will all gel together in the end.

The brain is an amazing thing - we often 'fill in' the missing pieces to make sense of an image without even realise that we are doing it!

I added some basic linework around the neck and collar to keep the whole picture in perspective.

Step 5: Time to Lose the Guidelines

Unfortunately, I had a fairly chunky eraser, but I managed to erase the guidelines without losing too much of my shading.

The shading I did lose was put back mainly by smudging from existing shading back over the erased areas.

I've also used an eraser to start shaping the lighter areas on the portrait, in sharpening the border between areas of high contrast.

I realised that the hairline was a bit too 'rounded', when in fact there is a certain squareness to it, so I reshaped that using an eraser.

Step 6: Finishing Touches

I know that the portrait looks unfinished, however I sometimes like to leave the peripheries such as clothing etc half done, it creates a sense of the picture being a piece of art rather than simply a copy. It also sometimes helps make the focus of your piece stand out, which is pretty cool.

Asides from smudging and erasing to fix up the light and dark shapes, I also returned to pencil work to add some of the finer details such as hair.

This is the final step for me - if I wanted to I would go back and fix the following:

- elongate the face...it looks much squatter than it should in my sketch

- fix the eyes: in the photo Steve is looking straight ahead, but my eyes are looking to the left

- lighten up the left eye - I seemed to have gotten a bit carried away with the shading over the iris and pupil!

Feel free to comment on other aspects that you would fix if you were working on this portrait - I promise not to be offended...it's how we learn!

Happy sketching :)