Make the curves of important outlines heavy. Minimize legends and captions. If an illustration is necessary but very complex, determine its essential elements and have it redrafted using only those elements. In order to make the poster as self-explanatory as possible, illustrations should be simple, large and clearly labeled. Color attracts attention and enhances the illustration.
Colors can easily differentiate zones on maps or highlight curves on drawings.
In addition, using a dark background with lines or line drawings in bright colors is very effective. Avoid Large Areas of White. The use of color is almost always effective in organizing ideas and data into groups of information that can be quickly assimilated. Make displays and lettering large enough to be read for viewing from a distance of 6-8 feet. Your design should attract viewers from 10 to 15 feet away while providing good readability at the 3 to 4 foot range.