Be Consistent
Select at most 2-3 fonts (one for title, one for headings, and one for body text). You can also choose one font and use bold or italics for emphasis and use different sizes to differentiate between headings and body text without using a different font.
Be Clear
Left justify all text and avoid centering. Make sure to select font that are easy to read, especially at a distance. Avoid script-style or very bold fonts.
Be Brief
Keep each text books to 50 words or less. Demonstrate concepts through graphics so that you do not overwhelm viewers with walls of texts. At a poster presentation, you will also be present with the poster to help explain your research, so do not re-write your paper on your poster.
The bold text in the image helps words stand out in paragraph format.