A startup venture is a series of hypotheses about who's a customer, what makes your product or service attractive to these customers, and so on. The Business Model Canvas and the Lean Startup Methodology provide a rigorous framework that you use to prove or disprove as many of these hypotheses as possible at as low a cost as possible. This method helps bring objectivity to the process so you don't delude yourself into thinking that the feedback is all necessarily positive.
These approaches complement each other and can be used to converge on insanely great products and services that meet customer needs and wants. Congratulations, you are on your way to reducing risk and upping your chances of creating a very promising startup!