Everyone is excited about their research and wants to share that excitement by saying EVERYTHING that you know about your topic. However, knowing that your poster will be one of many, you want to make sure that you viewers stop and get information from your poster – even at a glance.
Generally speaking, keep your text down to a few sentences; avoid paragraphs.
Make use of bullet points.
The poster on the top, it just too crowded. There is TOO much text. Poster session attendees are not likely going to spend much time reading this poster.
The poster below that has a good balance of text, bulleted information and graphics. It doesn't overwhelm the reader.
Tip: write down everything that you want to say and then start to ruthlessly condense and cut out words getting your text down to the most essential elements.