We use a .5 mm mechanical pencil, and often sharpen it on a separate sheet of paper before we apply it, so the tip is approximately .1 mm when we begin drawing on the actual paper. This sharpening is usually for more meticulous drawings. For other drawings, we just use the .5 mm tip.
We use many different kinds of paper, sometimes Strathmore, Arches, and for larger drawings we often use illustration board.
We sometimes employ a grid system for the larger drawings, and draw from a printed photograph that is the same size as we want the drawing to be -- which means we may have to cut up the photograph. For both large and small drawings, the process is just a visual translation, looking back and forth between the drawing and the photo. We don't usually use a projector, but have found it's useful for larger paintings.
To prevent smudging, we work from left to right, in rows, and cover up the finished parts of the drawing with plain paper (taping this protective cover-paper down as we move along).
To make really realistic drawings, it's usually best to use the entire value spectrum, the whole range of blacks and greys and whites, and keep layering and working into the drawing, over and over. By layering we mean that we finish a certain area, then purposefully blur it with a q-tip, so the darks and lights are greyed out, then go over that layer with a sharpened Tuff Stuff eraser, and again in pencil. Then we repeat the process, over and over. Some of our drawings have over 8-10 “layers” on them.
Paintings involve the same process of working from a photographic source and the same discipline of layering, except for a lot more mixing to find the correct color before application to the canvas.