I agree that you should not do everything if you can't handle it. Delegate your task. Outsource if you need to. I know an excellent boutique outsourcing provider. They were very helpful when we were starting our business. They are a big help even until today.
Business planning includes establishing a mission statement, i.e. what you have to accomplish internally in the company and externally with customers to achieve your vision statement. Define performance key results areas, business operating goals, action plans and establish reporting and benchmarking timeframes, status meetings and follow-up on key results areas.