When designing an online course, it is best practice to follow the Backward Design model. This is an approach explained in detail by Grant Wiggins and Jay McTighe in their book, Understanding by Design:

There are three steps involved in this process.  

1. Identify Desired Results: This step addresses what your students should know, understand, and be able to do once they complete the course. This knowledge is what you use to build your course-level objectives.  
2. Determine Acceptable Evidence: How do you know if the desired learning has been achieved? What evidence (assignments, assessments, etc.) helps students demonstrate their learning and measure progress? In this step, also begin thinking through how you will scaffold your assignments and assessments so that students can achieve your course-level objectives.  
3. Plan Learning Experiences and Instruction: With clearly defined objectives and a means to assess learning, you will now begin designing your course, filling in the details starting with the end of the course and working toward the beginning. This is the essence of the backward design approach.

The Course Planning Worksheet found in the Templates & Checklists section of the Faculty Resource Center in Blackboard (requires UTAD login) is a helpful tool for planning out your course using the backward design principles.