Maintain a cohesive feel to your website by following through design elements found elsewhere. At a minimum, echo colours and font and little design details such as rounded corners or image borders.
In this Knowsley Safari Experience website (knowsleysafariexperience.co.uk), the wavy background of the footer menu options echoes the wavy lines found elsewhere on the page.
Sometimes, you can use some creativity in getting your message across. For example, in this driving instructor website (drivinglessonsburystedmunds.co.uk), the website header illustrates the diverse types of learner drivers who could benefit from driving lessons with the school whereas the footer illustrates the different types of driving experiences that open up once you have gained "the freedom of the road". Both follow a similar visual format:
In this cleaning company website (elitecleanteam.co.uk), the header photos rotate behind a central watersplash; in the footer, this water splash is stretched to form the top frame for images depicting the type of cleaning services offered (see section 1 above). Note how the different text sections of the footer are visually separated by using different levels of background opacity.