Informal outlines usually take the shape of a semi-organized list of ideas that you want to mention in the work. These make it easier to reorganize information later while you revise; however, brainstorming lists are a great way to start this type of plan. To help keep this organization focused, try crossing out ideas that you know you don't need to mention and ideas that you add as you create your draft. You'll be better able to see where the rest of your ideas can fit into what you're writing as you go along.
Begin by writing your main idea in the middle of the paper and circling it. Draw lines branching out from the center that connect to ideas related to the main topic and circle them. Continue to branch out from these circles with supporting information. Clustering works a lot like a formal outline, only taking a much different shape. This type of planning can work well for more visual learners. If you use the clustering technique, while you're drafting, think about your readers and what order of information they would best respond to in your later, more structured paper.
Formal OutlinesFormal outlines follow a more structured path. You've probably seen these or used them before. They generally begin with the main point or thesis statement. The rest of the outline consists of headings that explain major ideas plus subheadings that identify supporting material for each of them. This method shows relationships between ideas and groups related points for a more solid organizational plan.