Depending on your specific teaching role, you may have to create a syllabus or you may wish to create a supplement for your lab or discussion section. Here's an article that will give you advice on where to start and what should be included on your syllabus. In addition, here are tips for writing and some sample language. And, here's very cool tool that automatically generates the dates for your course in any given semester.
If you're designing your own course, "course mapping" is a great way to start. Try this Course Mapping Guide, which walks you through the steps and helps you think clearly about learning objectives.
It can be helpful to look at a sample syllabus. Here is one for a lab section and one for a lecture course. Additionally some William & Mary syllabi are accessible online for you to look at. Ask around; most people are willing to share syllabi. When looking at sample syllabi, look for characteristics you like and those you find confusing. Learn from these.
William & Mary recommends several policy-related statements you may want to include on your syllabus:
You may want to include a reminder of W&M's honor pledge.
You may also want to adopt a diversity and inclusion statement