The basic material for learning sketching is the dark shade pencil either 6B or 8B whichever is available and a sketch book. We usually avoid rubbing or use of rubber as much as possible and try to bring out shades with use of pencil only. There are many brands available in India with both 6B and 8B easily available (Faber-Castell, Camlin). No need to go for very costly pencils or import brands.
Sketch a lot! Don't think about the result, just let your hand practice its natural movement. The only advise I can give for good sketching is practice, practice and practice.
The basic steps and lessons of the sketching may not seem interesting or may be boring, but they are the ones that make you perfect for further difficult tasks of sketching and drawing. These basic steps have to be mastered and then only you should move ahead.
The basic of pencils
The pencils are available in varying shades of hardness and softness, ranging from 6H to 9B, where H stands for hardness and B stands for black or softness of the pencils.
Sizes of papers
The A0 size print measures 84.1 x 118.9cm, 33.11 x 46.81 inches.
The A1 size print measures 59.4 x 84.1cm, 23.39 x 33.11 inches.
The A2 size print measures 42.0 x 59.4cm, 16.53 x 23.39 inches.
The A3 size print measures 29.7 x 42.0cm, 11.69 x 16.53 inches.
The A4 size print measures 21.0 x 29.7cm, 8.27 x 11.69 inches.
Lesson 1 - Box shading
Use a ruler and draw 1.5cm x 5 cm boxes and start shading them from very light to darkest possible in steps as shown below in the figure, this is from the learner's sketch book
Lesson 2 - shade Mixing
Lesson 3 - Graphs
Lesson 4 - Stick drawing