120-point type is advised for your title, and 14 point is the smallest advised for text. Numbers of graphs and charts may need to be smaller, however. Readers are put off by lengthy text. Graphics can effectively take the place of text. Graphics also draw people's attention to your poster.
Color can create a dynamic display.
Visual studies show that bright reds, oranges and yellows can be a distracting irritant, while subtle blues and grays are calming and appealing. Colored and textured backgrounds can be appealing, and are no more expensive to print out, just make sure the texture doesn't distract from the text. Color photographs are attention grabbing, and very effective when combined with concise, legible captions. Make sure that you scan them at 150 dpi at the exact size they will be when printed. It will just slow your computer down, hog valuable computer resources and not make a noticeable difference to the human eye when printed out.