The diagrams should be simple.
Each diagram must be given a clear, concise and suitable title without damaging clarity.
A proper proportion between height and width must be maintained in order to avoid an unpleasant look.
Select a proper scale; it should be in even numbers or in multiples of five or ten.
e.g. 25,50, 75 or 10, 20, 30, 40, .... etc. But no fixed rule.
In order to clear certain points, always put footnotes.
An index, explaining different lines, shades and colors should be given.
Diagrams should be absolutely neat and clean.