Strategy is the approach or plan of action to achieve your major idea. Observe, ask questions, create surveys, research, brainstorm, and define your goals as part of your strategy. Developing your strategy will help you define the kind of experience you as a designer want to give your users.
Ask yourself these questions in your initial design process:
What we want to get out of this product?
What do our users want to get out of it?
Create user personas and user scenarios/use cases to understand your users. Conduct questionnaires and surveys to get insight on how your app can solve real problems that people may have.