The adoption of CSS3 has provided many possibilities for creating beautiful visual effects without using image files. Here is an example: on an early iteration of the design of the various headings on GoToQuiz, I used this sprite combined with CSS to create the rounded color bar appearance.
I’ll describe an easy prefetch technique useful in situations in which you are reasonably sure the user will navigate from Page A to Page B. This situation typically involves the user filling out a form. Chances are high that if a user begins to fill out a form, she will eventually submit it, arriving at Page B. If you prefetch resources that will be needed by Page B, it’ll load faster when the user navigates to it. This is a technique I’m using on our lifespan test.