Contrast in typography can be achieved through size, weight, and proportions of different fonts. One rule is to use sans-serif fonts for headlines and serif fonts for body text. Helvetica is both legible at small sizes and suitable for headlines. Certain fonts like Comic Sans, Papyrus, and Curlz MT should be avoided as they can detract from good design. Eyelines that align elements across a spread can create movement and unity in a layout. White space, whether between characters or in margins, can create a clean or chaotic look. Impact can be established through sound typography, eyelines, white space, or simplicity in design.