Every word displayed in an application is part of a conversation with users. This conversation is an opportunity to provide clarity and to help people feel comfortable in the system.
Use terminology that is familiar and easy to understand for the target audience (i.e. Persona) of your application.
Start your sentence with the most important objective first.
Use short words, active verbs and common nouns.
Avoid Contractions such as “Don’t”, “Won’t”, etc.
Avoid abbreviations (including ampersand instead of ‘and’), acronyms, and tech-babble.
Use an informal and friendly tone, but not too informal or humorous.
Avoid popular, but transient, words and phrases.
Keep information short and consistent; avoid redundancy or wordiness. e.g. Do not repeat the dialog title in the dialog text.
Don’t abuse Capitalization because it draws people’s attention.
For date and time information, consider that your app may potentially be used for several years; do not use immutable date references like this year unless it is algorithmically determined.
Follow system-wide wording conventions for basic functions to keep wording consistent.
In general, exclamation points should be used sparingly in user-interface strings. In particular, they should not be used for error messages, to avoid an effect upon the user similar to WRITING IN ALL-CAPS.