The following are key elements of design and layout you should consider when creating a poster.
A poster should include a banner at the top which includes the title, and author(s) and their affiliations. The title needs to be large enough to be read from several feet away (typically a point size of 100 points or more). The authors and affiliations should be a smaller font than the title, but larger that the text in the body of the poster.
Below the banner, a poster usually includes three or four columns of content. There are exceptions; in some cases you may opt not to break the content into columns.
Headings, columns, and graphics should be aligned whenever appropriate. For example, a poster is typically broken into columns. the tops of the columns should be aligned with each other, and the sections in each column should be left justified so that each paragraph is exactly at the left edge of the column.
Align graphics where possible. For example, you could align the top edge of a photo in one column with the bottom edge of a diagram in another column.
Distribute the content and images in the poster so that it looks balanced. Strive to achieve an aesthetically pleasing, uncluttered look. Include a margin of about an inch along all edges of the poster.
Be sure to include enough white space. If everything is jammed together it will make the poster difficult to read and less appealing aesthetically. How much white space is enough? This is difficult to say. It is a judgment call. If the poster is too dense, delete nonessential material too allow for white space.
Use the same fonts throughout the poster. Use similar dimensions for illustrations and photographs. Use similar color and design elements throughout the poster.
Use color judiciously to add to the visual appeal of your poster. Consider using one or two accent colors (such as for shadows or or thin lines separating columns) or using a pale background color. But too intense or too many colors can be distracting and annoying. Use either black or dark-colored text.
Use either serif or sans serif fonts, but be consistent in your use of fonts, and do not use too many fonts (usually only one) in your poster.
In general it is good to use a sans serif font (such as Arial or Helvetica) for the title and headings. Text may be either serif (such as Times) or sans serif.
This is is a sans serif font
This is a serif font
For more information about serif and sans serif fonts, see Easil's article on serif and sans-serif fonts.
Divide the poster into parts with major headings for each part, and where appropriate, minor headings within the major sections. Make heading for each level distinct and consistent, so that the viewer can easily see the structure of the content. You may also choose to add color to a level to set it apart. For example:
Heading level one
Heading level two
It is important that your title and headings stand out, so people can quickly see what your poster is about and how it is structured. The font sizes you should use depends on your overall poster size as well as the amount of content in your poster, and it is somewhat subjective. But some general suggested sizes would be:
Title: 88 to 120 points
Names and Affiliations: 70 to 90 points
Major headings: 54 to 80 points
Sub headings: 48 to 72 points
Text: 36 to 52 points
The above are only guidelines. When you have completed a draft, take a look at your font sizes and tweak them as needed to make them look good.
Generally speaking, titles and headings should be bold. Text should not be bold.