When you’re laying out your poster, instead of typing in the title you put in your abstract, put this:
“No one has to read this crap.”
Frame grab from this interview with Ed Yong. Ed has this posted above his desk as advice for freelancers, but the advice is equally appropriate for poster makers.
Nobody owes your their time at a conference. Nobody has to stop at your poster. Nobody has to talk to you.
Let that harsh realization guide your editing and design to make something that another person, who is not you, who is not invested in the project, wants to read.
Update, 1 October 2015: This quote apparently originated with Tim Radford. (Radford’s rule #6.)