Michael Porter is an accepted management guru who currently leads the Institute for Strategy and Competitiveness at Harvard Business School. Porter best known for his work on Competitive Strategy and Competitive Advantage.

In a Harvard Business Review article entitled What is Strategy, Porter has this to say:

The essence of strategy is deciding what not to do.

For a startup, there is no better advice. Saying "No" is more important than pursuing every possible opportunity. Don't go chasing the buzzwords and the new new things. Say "No," stay focused on your strategy, keep executing.