You don't necessarily have to do any research before you start your business plan. You can dive right in, and as you work your way through LivePlan, it will help you see where you might need to supplement your knowledge of your market and industry.
If you'd like to gather some data ahead of time, however, to help your plan progress more quickly, here are some good areas to focus on.
Identify your target customer
So much of your business plan will flow from this one idea. You know what product or service your business will sell, but who, exactly, will you be selling it to? Try to come up with as specific a description as possible: what is your ideal customer's age range, gender, average income, where do they live, what are their hobbies? These articles may be helpful: How to Do Market Research, Practical Market Research Resources for Entrepreneurs, and TAM, SAM, and SOM - Huh?
Identify the problem your business solves
If this idea seems daunting, don't worry - you're not alone. But again, a lot of your business plan flows from this key idea. If you're not sure what problem your business is solving for your target customer, read Find a problem worth solving and How do you know if you have a good idea for a business?
List your revenue sources
A good way to get a jump start on your business plan forecast is to make a quick list of where your revenue will come from. What products? What services? Which ones will be primary sources of revenue, and which ones will be secondary?
List your costs
Similarly, making a simple list of where your primary costs will come from is a helpful way to prepare for forecasting. Will you have a lease to pay? Employees to hire? Raw materials or packaging to buy? List all the costs you can think of now. As you work on the forecast, LivePlan will likely suggest some additional ones.