Here are some poster presentation suggestions...
Text
Make it big (I use 20 pt. and then blow it up 150% for regular text--larger for title, authors).
Use a serif font like Times Roman-it's easier to read than other fonts.
Limit your words--can you use bullets, tables, figures, to get your point across instead?
Don't use all capitals or put whole paragraphs in bold--they're harder to read.
Because there aren't many words on posters, make sure you make the best use of what you have. Avoid passive voice. Don't leave in any words that aren't needed-"the results showed that", etc.
Start and end strong. Re-read your first couple of sentences. If they don't add anything, cut them. Do the same with your last couple of sentences.
Graphs
3-D graphs are hard to read.
Make sure your colors and patterns are easy to read and don't compete with each other.
Avoid chartjunk like grid lines that add ink without adding information.
Tables
Don't be redundant with text or figures, or even within your table. For example, if you say 40% of your sample was male, you don’t need to tell us that 60% was female--we can figure that out on our own.
Layout
Be careful with the use of color. Print should always be black on white or off-white paper. Black text is much easier to read, particularly if people are doing a lot of reading (which you hope they are). If you want to use color backings or color in graphs, fine, but be careful of the colors you choose. You don't want to use anything too bright or jarring.
Lay out your poster in columns. This makes it easier for people to read and follow, even in a crowded room.
Peripheral cues (color, pictures, etc.) can attract people to your poster, but remember 1) the content is the important thing--you want a clear and understandable, readable description of your study first and foremost; and 2) you want to look professional. Hand drawn signs, childish pictures, pictures that don’t add anything to your poster, etc. aren’t likely to be impressive (unless maybe your poster is on children’s drawings or something else where it would be relevant).
Be careful of lamination. It can look nice, and it makes the slides sturdier. But depending on the light in the room where you’re presenting, it can cause glares that make your poster hard to read. Other ways to reinforce the paper you print your poster slides on is to use colorful cardboard backings (that “frame” the pages) or to use card stock--heavier paper that’s readily available at your local copy store.
What to include
Title, author, affiliation
Abstract
Introduction--brief review of theories behind research and/or past research, purpose, hypotheses
Method--who your participants were, what happened to them. You may have tables or figures as part of the method.
Results--brief description of results. Should be supplemented by tables and/or figures.
Discussion--brief statement of what your results mean, acknowledgement of limitations, implications of your findings.
References--can be smaller print that other parts of your poster, but should still be there.
Presentation of the poster
Lay everything out ahead of time--find out what dimensions the poster board will be if possible.
Don't forget to bring pins.
Bring handouts (your poster reformatted as a regular document) to give to interested people.
Dress professionally.
Stand by your poster during the poster session. Be friendly and polite when people come by. You may want to ask them if they have done work in this area or if they are interested in your area. You can get great suggestions by talking to people about your poster. You may also want to think about how you would summarize the poster ahead of time. Some people may like to be "walked through" your poster.
Margins
To print your poster out on 8.5 by 11 paper and then blow it up to 11 by 17, use the following margins:
landscape orientation
top .25"
bottom 1.3"
left .25"
right .25"
Then blow it up 150%--it will fit nicely on the larger paper. Also, you can single space and it will look nice, since blowing it up will make more room between lines.
Other sites on posters:
http://www.psichi.org/conventions/tips.asp
http://www.kumc.edu/SAH/OTEd/jradel/Poster_Presentations/PstrStart.html
http://www.conferencesandmeetings.org/posters.htm
http://www.lemoyne.edu/OTRP/otrpresources/poster.html