Keep the size of your images as small as possible. While serif fonts such as Times New Roman are generally easier to read in print, sans-serif fonts such as Arial and Verdana tend to be easier to read on screen. Make sure your navigation scheme is easy to read, easy to use, and consistent throughout your site. Less is more. Too many graphics, colors, and extraneous elements in your page can take away from your content.
Users already have expectations.
While these may or may not be wise design decisions, keep in mind that users already expect them. Any images that you use or create must be saved in either .gif, .jpg, or .png format. Adobe Photoshop is available on the Applications Server for developers who need to do some image creation or manipulation.