Text size

Your poster needs to be visible from a distance. Using large fonts will make your poster easier to read and limit the amount of text you can put on the poster. A common mistake people make when designing posters is putting large amounts of very small text. Writing concisely and only including essential information will help you keep your word count down. 

Print out an A4 version of your poster to check the font size. If you can't read it easily then the font size is too small.