I have been a fan of Harvard Business School Professor Michael Porter since 1987 when I was first taught his famous 5 forces model and read his seminal 1980 book Competitive Strategy: Techniques for Analyzing Industries and Competitors which has been reprinted numerous times. (en.wikipedia.org/wiki/Michael_Porter, en.wikipedia.org/wiki/Porter%27s_five_forces_analysis, www.amazon.ca/Competitive-Strategy-Techniques-Industries-Competitors/dp/0684841487 and youexec.com/book-summaries/competitive-strategy-by-michael-porter)
Linked here is a 70' presentation by Michael Porter from 2015 in which he eloquently covers all the key issues related to business strategy: He describes strategy as competing to be unique, to chose to do things differently as a differentiator or cost leader. As part of the strategy, the value proposition involves which customers you serve (recognizing that you can't serve them all well and profitably), their need (or perhaps Job-To-Be-Done) and your pricing strategy (or perhaps business model). He goes on to argue that the business strategy should not be a secret but instead be a widely known and shared foundation to help drive decision making on what new avenues to pursue as well as how to make the inherent trade-offs that arise.
Michael Porter's thinking fits well with my entrepreneurial/intrapreneurial emphasis on "Magic" which encompasses doing something differently and business plans which I see as a written manifestation of the business strategy. (no-magic-no-business-opportunity.html and to-draft-a-business-plan-or-not.html)