Justify your text & ensure that lines don't break in the middle of words.
Use a standard, simple font such as Times New Roman, Calibri, or Arial.
Use large font & make section headings bold and/or a bit larger.
Dark text on light background is best. It is easiest to read and uses less ink when printing.
There are various PowerPoint templates available online for poster presentations, including the first few at this Microsoft link. If you use a template you find online from another person or institution, include a small note about the template source.
There should be logical flow between sections. A standard arrangement is columns followed top to bottom and left to right.
For more information on posters please go this set website: http://libguides.dbq.edu/apex
Canva: An easy to understand website for creating a variety of documents. Make sure you create your document with inches not pixels. Save often. Download as a JPG.
PowerPoint: A popular, easy-to-use option. It is part of Microsoft Office package and is available on campus computers. (Advice for creating a poster with PowerPoint).
Publisher: A lot of the same elements as PowerPoint. Available on campus computers. Click here for sample template.
Open Source Alternatives: OpenOffice in the free alternative to MS Office (Impress is its PowerPoint alternative). Inkscape and Gimp are alternatives to Adobe products. For charts and diagrams try Gliffy or Lovely Charts. A complete list of free graphics software.
Pixabay: Website with free images to use in your poster. Download large images so they won't pixelate on your poster.