Which Pencils are indicated for a nice look of your portrait or pencil drawing?
For a qualitative shading and blending, you shoud use an 0.3mm - 0.7mm mechanical pencil loaded with 2B - 3B since you start to draw. This gives you a nice line at all times without the need to permanent sharpe. When you buy these pencils they are usually sold with HB leads, so be sure you buy an extra pack of 2B or 3B to replace the HB deads. Unlike the wooden pencil, you can't use the side of the lead to shade large areas, instead, the shading is kept very tight and the varying tones are achieved by gradation and layering, with the pencil strokes always following the shape of your object. I find that smooth, dark areas are best achieved by alternate layering and blending rather than extra more pressure on the pencil. You can apply 5 till 6 (or more) layers of pencil to an area of dark shadow or hair.
Blending Stumps and Tortillons
These are spirals of wound paper that are used to blend the pencil shading. It is important to keep the tortillons clean when using in light areas but a selection can be kept in varying stages of cleanliness using the blackest for large dark areas or even for drawing in shapes. Here you can find a picture of my Tortillons: