You don't want your site to look like a group of unrelated pages. Decide on the general layout. Sketch out a 'template' page. Backgrounds should be consistent. Many sites now use a vertical strip, stripe, or graphic down the left side of the page.
Many sites place the menu in a frame at the left of the page.
Since many of us will be making pages for our students to access and many of these students may be accessing them from home or dorm through a modem, size is something that must be taken into consideration. This is a very rough estimate. Using this formula, a 30K graphic would take 32 seconds to download. A typical 30-35K graphic may download in less than a second on a 56K or T1 line but it would take over a minute to download using a typical 14.4 kbps modem. Larger graphics take much longer.