Great suggestions @sme!
I always find the Business Model Canvas (or the Lean Startup Canvas) as a great tool for any new business owner to sit down and develop
More concise than a business plan, it gives you a nice framework to establish the important strategic elements of your business... one that can constantly be referenced and refined as your business grows.
Business Model Canvas is a solid tool and really simple too. When I first wanted to get something off the ground I spun my wheels trying to build a formal business plan... Changes always happen. Keeping a plan generalized is key for responding to how your business evolves.