Content - Again, you will die a horrible death at the hands of teachers and admins if they event think that something is inappropriate. Monitor all content. Check for spelling, file size, uniformity and everything else you think about. Make the site look professional or it will come back to haunt you. You will really want to start making your site look cool once you get the hang of things.
Presentation is everything.
People will want to come back if it looks cool. Following are some ideas to make it better. JavaScript - Learn this. The Definitive Resource is the book to buy. It will teach you what you need to get started and then some.