Ensure that you use plain formatting in your resume to accent and highlight important parts, but do not distract from the content.
Standard fonts should be used for the same reason. Stick with fonts such as Arial, Times New Roman, etc…
Use a minimum number of font sizes throughout your resume. Most sources suggest using no more than 2 or 3 different sizes of the same font.
No matter what font or sizes you pick, be sure nothing is too small or too large. The key in resumes is moderation, especially for formatting.
Unless you are in an artistic field, do not use pictures or clip-art on your resume. Once again, this is distracting.
To keep your resume from being monotonous, break up paragraphs with bullets. This also makes for quicker and easier reading.
Just be sure your bullets are plain. Do not use anything like Wing Dings. Also, limit yourself to one or two types of bullets throughout.
Do not fill every spot on your page with text. By using space effectively you can give your reader’s eye a break and draw attention to certain sections.
Whether you use hyphens or dashes, be sure to remain consistent. Do not use a hyphen to separate one date range, then shift to a dash for the next one.
Facilitate quick reading by aligning your dates and position titles in a column.
Find out if your industry has an expected length for resumes, and stick with it. For example, legal resumes are widely accepted to be only one page.
If your industry allows (or even encourages) more than one page resumes, be sure to use effective page headers for subsequent pages. Remind your reader who he is reading about, and also make sure pages 2+ do not get irretrievably separated from page 1.