The first point to keep in mind about business plans is... have a business plan! This may seem obvious but is overlooked. Many people start businesses without a plan; sometimes it can come from sheer bravado, thinking "I don't need a plan", or alternatively you might hear "It's all inside my head, that's my business plan".
Contextualise Your Budget : Of course your budget will be extremely important. But sometimes people sort of pluck figures out of thin air, not giving it the context it needs in the business plan to make real concrete sense of how that budget is going to work.
Be Prepared For Risks : It is a fact of life that any new business or enterprise has a degree of risk attached to it. Therefore it is important for your business plan to analyse and calculate that risk, showing how you will engage with it. There is no business plan out there that is risk-free, but very often where the risk is higher then the rewards will be as well.
Drawing functional Plan: After positive result form the feasibility study, functional plans are drawn up. Some scholars and writers prefer to include feasibility study with functional plan but the two have been taken separately. Whereas only after the feasibility study can one go into the derails of drawing up functional plans which would determine the strategies for all the operational areas : marketing, Finance and production.