Over the last couple of years working on Dump Truck Dispatcher, we have tried to create an easy-to-use, consistent interface. Our walkthrough of the application https://dumptruckdispatcher.com will highlight some of the patterns we used to provide feedback to the user.
We'll also spend time discussing our validation and error handling strategy. We wanted to be sure that whether the error happens on the server side or the client side, that the user can't tell the difference and gets a user-friendly message telling them what went wrong.
Finally, we'll spend time looking at datatables.net and how it can be used to display lists of data with decent mobile responsive behavior.