copywriting - Best practices for application alerts

As a developer, I'm always confused about the three basic values of any application's alert:

1. Title


2. Message


3. Dismiss button

What should be placed in those 3 values? FAQ for myself:

• Should the title be a resume of what happened or where the message came from?


• Should messages use exclamations?



• Should messages be complete sentences (ending with a full stop)?


• How much detail should the message contain?

Well, as a single question: there is some basic rules while writing alert/notification messages? Bonus if these basic rules answer my minor questions.

Please share your thoughts...

Answer

All of this is documented by Google in their writing guidelines.

http://www.google.com/design/spec/style/writing.html

Use contractions, avoid exclamation marks, be brief, keep it simple, use numerals in place of words, avoid slang, use punctuation when writing more than one sentence, use easy to understand language.