I teach that you should seek to learn from competitors; obviously never copy another business's idea or what they are doing, but you can absolutely learn from their mistakes or see what they are doing and discover ways to improve it. All of that analysis belongs in your business plan: make sure you have your competitors under the microscope and make sure that is a solid chunk of your plan. That is some of the best research and information you will gather about what will make your business successful in future.
Some people think that they do not need a business plan for a small business. But let me make it clear that the size of the business doesn't matter. Whether small or big, you need a plan. If you need a plan as an individual and for your family, then why not have a plan for your small business? Like for individuals and families, you need to plan for your online small business. A business plan shows you what you would like to achieve and how to achieve it. Although not all plans are written down, a good business plan should be written down. If you have it in your head, it's high time you spent some time to write it down for better results.