The best way to blend your drawing when drawing realistic faces is by using a tortillion. Because instead of having to use your fingers to blend the shadings, which can be a little bit messy and uncontrollable, you can use the fine tip of the tortillon instead, which is more manageable. This can make your drawing much cleaner and your smudges more smoother, which affects the overall appearance of your sketch.
You can actually buy a tortillion in art shops, but it’s really not that hard to create your own so I pointed out here step by step instructions to help you make one. All you need to have is a piece of paper, a masking tape and a pair of scissors, a ruler, and a pencil to mark the measurements.
1. You need to cut a piece of paper and reduce it into 6 by 3 inch ones.
2. Mark the paper at the top 3 and half inches, and at the right from bottom 1 inch. Connect a diagonal line to the end of these measurements. Now cut the top right hand of the corner from that diagonal.
3. You should now fold the paper from the right with a small angle. This is to prepare it for rolling.
4. You should now roll the paper from right to left. This will produce a pointed tip for the tortillion. Maintain a good angle to do so, as you keep rolling the paper.
5. The tortillion will look like a pencil made of paper with a pointed tip once it is finished. Put a tape at the body once you have finished rolling.
Now you have your very own homemade tortillion. You can now use this tortillon to blend the shadings of your sketch. Use this as you see fit and as is required in the drawing. Just use the eraser if you want to clean tip of your tortillion after using it.
You can also check the complete instructions (with pictures) on how to make a tortillion on my blog, Drawing Faces. This article, How To Make A Tortillon is released under a creative commons attribution license.