Providing access to users with disabilities is not just a good idea, it's fast becoming the law. A few adjustments will do the trick, and most of these guidelines will help all viewers:

• Text should be easily visible at a reasonable distance from the sign.
• Always ensure that text colors have high contrast with the background color.
• Keep your font sizes large, especially for your main messages. To test font size, create a test screen with lines of different font sizes and have people view the screen at the farthest practical distance. Remember too that people may view the screen as they pass by.
• The exception to this would be for screens meant for interaction, where the user is standing directly in front of the sign. Even here though, keep in mind older viewers with limited vision or low vision viewers.
• Serif fonts work well for long text passages, but digital signs are the wrong medium for paragraphs of text. It's best to stick with sans-serif fonts.

Simple, relevant images are better than complex ones that draw the attention away from your message

• When creating graphics or video, specify a size that matches or exceeds the output resolution you have selected. Technology will generally scale down higher resolution media for a lower resolution screen (though perfectly matched media looks best), but low resolution media will not look great on a high-res digital sign.
• Also use On-screen Show 16:10 aspect ratio such as 16:10 or 16:9 as much as possible for your media, since you may want to repurpose that media. Your layouts are much easier to create if you have consistently sized pieces to work with.
• When developing a screen with multiple content zones, remember that less (fewer zones such as two) is often more (effective), as too much information will overload and disinterest many viewers. A lot depends on how close your viewers will be to the sign, how much viewing time you expect each person will spend.

Digital signage is not a place for writing paragraphs. It is more communications at a glance, so think of your viewers grabbing glances of content at a time. 

• Keep your words few and short. Rewrite a few times to get it progressively more concise 
• Write in phrases rather than full sentences 
• Use active voice and action verbs 
• Preview designs - Stand back at least 6 feet from the monitor. Read content forward and backward to gauge how long a new viewer might take to read the message entirely. 

Getting your viewers to act requires a simple, strong, clear message.

• Use strong verbs in a concise phrase
• Give the specifics needed to act (e.g., dates, places, phone numbers)
• One way to highlight the call to action is by using a text color that contrasts with the other colors used

Time delay o If your sign presents a rotating series of screens, consider the environment when deciding the loop length:

• A medical office waiting room would probably warrant a longer time between screens, as patients have time to read and want to maintain a relaxed ambiance.
• A hallway where people busily rush by may call for a short delay, as a screen change may grab their attention. Yet the viewer must have time to read the message.
• For a refreshing non-pattern feel, try mixing the duration times from screen to screen in a set.

Keep your content fresh, or your viewers are likely to start ignoring your signs. Strategies for doing this include:

• Keeping a large stock of imagery to swap in/out
• Alternating your layouts so viewers notice a change
• Creating multiple versions of the same message in different looks
• Varying the time that screens are shown
• Employing a small bit of motion in a previously static screen

Before you make a screen public, test it to make sure that what you saw on the computer is what you expected it to look like on the actual signs, especially with regard to aspect ratios and readability from likely viewing distances.

Learn your audience

Try experiments with your content and watch to see which techniques increase dwell time (the time passersby spend actively reading and/or interacting with a sign). You get only 1.5 - 3 seconds of full attention for glance media. Thus, any period when important text or other critical message components are off the screen is potentially a missed opportunity to connect.

Leave enough time to read the text.

Don't trust your own judgment -- if you're the designer, find somebody who hasn't seen the content before and have them read it. If they can't read your message at least three times in the allotted amount of time, either take out some text or leave it on screen longer.

Good slides follow the 3 x 5 Rule:

• Don't pack the message with too much text.
• Keep the type size as large as possible, especially for headlines.
• Utilize either three lines of text with five words, or five lines with three words.