Keep content fresh. Perform monthly maintenance. Set calendar reminders for yourself to update time-sensitive pages like event calendars or posted deadlines.
Use white space aesthetically. If your text is too dense, people won't read it. Bullet or number succinct bits of information.
Keep graphics efficient. You may think your 200kb graphic is wonderful, but it will never show up on most users' screens (especially those on slower modems) as they just won't wait long enough to see it. Keep page sizes below 30k if you can (unless your graphics are the 'point' of the page).
Keep your navigation really simple. Work out a consistent navigation style and stick with it. Try not to overload your pages with hundreds of choices that will confuse your visitors. Five to nine choices is the optimum.
Use color to distinguish visited and unvisited links. Knowing where you've been is one of the basic features that all navigation designs should support.
Always include contact information: phone, email.
Test your pages by viewing them on multiple browsers and platforms. If possible, test it from your home computer.