Clarity and cogency are the most important objectives for your drawings.
To achieve a convincing elegance (elegance is very convincing) make sure the drawing is well placed within the sheet of paper.
Do not crowd the sheet of paper. It makes the person looking on feel as if the design has no controol over itself. A lot of space is quiet, calm, controlled.
It is often a good device to place the drawing slightly off-centre, leaving a lot of blank space around it and especially to one side. This side can then receive annotations such as a small text, a quotation or emblem, which embodies the leading idea around which your design has developed.
Make sure that the composition is clear; do not clutter your drawings too much with superfluous “effects”. Economy is far more elegant and convincing than clutter.
Make sure that any lettering does not dominate the drawing, but that it enhances the composition of the sheet as a whole.
Devise systems to enhance the clarity of your design, using colour and other code systems.
Brightly coloured papers, such as dark browns, bright yellows, deep pinks, purples and blacks are very difficult to use successfully for a presentation drawing. In fact, I personally have yet to see examples where such drawings have been an unequivocal success. Usually they succeed only in looking tacky. Lines and colours on such a background often lose their brilliance. For this reason it may be better to stick to whites and pale shades of grey, cream or vanilla.