User experience is the first thing that most successful designers would like to sleep on. Good user experience not only multiplies the effects of a good design/layout but also contributes to the success of the product. Creating a good user experience is not rocket science.
With some common sense and the right selection of tools, you designs can deliver performance and pleasure. Take the example of Tokeninput, it is a simple jQuery plugin that you can use on your website or web application to ease data selection for users. Tokeninout allows users to search and select multiple optons as they type in a simple text box -same as on Facebook.
You can replace long lists of check boxes or large selection box with a simple, Facebook-style that users can use to select multiple option from a give list and they type in.
Tokeninput is easy to skin suing simple CSS. It is compatible with PHP, ASP.Net, Django and all JSON enabled back-ends. It also caches result on client side to reduce load on server.