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.
Planning is the first and the most crucial step for starting a business. Business Planning lays down step-by-step procedure by which would function. The various functional requirements of business-marketing, finance, human resource and production, provide information to all the concerned people like employees, venture capitalists, etc. and it also draws a read map to help the entrepreneur run the business successfully.
Have you done your research? Do you really know that the people you will be targeting want your product / service, and crucially do they want it AT THE PRICE that you will be offering it at? Whilst confidence in your plan is fantastic, you must make sure that it does not lead you down a blind alley along a path that is not desired by your target market. Don't assume what customers want, do your research and make sure that is clear from the start in your business plan.
Most of all if you are seeking funding for your business, it will be absolutely crucial to go along and show someone an actual plan, because there will be very few people who will loan you money on the basis of what's just in your head. So it's pivotal to have a plan and be committed to preparing that document.