How to get users to read error messages?

Question

If you program for a nontechnical audience, you find yourself at a high risk that users will not read your carefully worded and enlightening error messages, but just click o

Answer 1

I'd suggest that you give feedback (stating that the user made a mistake) immediately after the mistake is made. (For instance, when entering a value of a date field, check the value and, if it is wrong, make the input field visually different).

If there are errors on the page (I'm more into web development, hence I'm referring to it as a "page", but it can be also called "form"), show an "error summary", explaining that there were errors and a bulleted list of what exactly errors happened. However, if there are more than 5-6 words per message, those won't be read/understood.