Draft a rough outline of the most important items to be taught. Figure out how much time teaching each item will take. Pare down the number of items if you don't have enough time to teach everything.
Get a list of students taking your course, as well as their background. A legal course designed for property lawyers, for example, should be quite different than a legal course planned for real estate agents.
Look for appropriate resources to teach the class. Don't overload the students with books that won't be used. Find practical texts that can be used in everyday life.
Find case studies that support your lessons. Include both statutory and judicial proceedings. Plan your course to allow time for practical skill development, such as legal drafting, argument and analysis.
Ask your supervisors to approve your syllabus. Ask others who have taught similar classes for their ideas on teaching the class, as well as an assessment of your proposed syllabus.