Building a successful app is a complex process that requires careful planning and execution. Here is a step-by-step guide to help you build a successful app for your startup:

1. Define your app idea: The first step is to clearly define what your app will do and who it will serve. You should also research your competition and identify any gaps in the market that your app can fill.

2. Conduct a feasibility study: Conduct a thorough market research and assess the feasibility of your app idea. Consider factors such as demand, target audience, and revenue potential.

3. Build a minimum viable product (MVP): Your MVP is a basic version of your app that contains only the essential features. This allows you to test your app with a small group of users and gather feedback.

4. Design and develop your app: Once you have validated your MVP, you can start designing and developing your app. Choose a development platform, such as iOS or Android, and hire a team of developers to build your app.

5. Test your app: Test your app thoroughly to ensure it is user-friendly, stable, and meets all the necessary requirements. This is also the time to fix any bugs and make any necessary changes.

6. Launch your app: Once your app is ready, it's time to launch it. Choose the right channels to promote your app, such as social media, app stores, and press releases.

7. Monitor and analyze: Continuously monitor and analyze the performance of your app. Gather user feedback, track downloads, and make improvements to your app as needed.

8. Expand your app: As your app grows, you may need to add new features and functionality. This can help you to retain existing users and attract new ones

9. Monetize your app: Decide on a revenue model for your app. This could include in-app purchases, subscriptions, advertising, or a combination of these.

10. Focus on security: Security is crucial for any app, especially if it involves handling sensitive user data. Make sure to implement robust security measures to protect your users' data.

11. Pay attention to user experience (UX): A great user experience is key to the success of your app. Make sure your app is intuitive, easy to use, and provides value to your users.

12. Engage with your users: Engage with your users through various channels, such as social media, in-app messaging, or email. Listen to their feedback and make improvements to your app based on their suggestions.

13. Build a strong brand: A strong brand can help you differentiate your app from the competition and build a loyal user base. Focus on creating a consistent visual identity and messaging for your app.

14. Leverage data and analytics: Data and analytics can help you understand how your app is performing and what your users are doing. Use this information to make informed decisions about future updates and features.

15. Stay updated: The tech landscape is constantly changing, so it's important to stay updated on the latest trends and developments in app development. This can help you stay ahead of the competition and continue to innovate.

By following these steps, you can build a successful app for your startup. However, it's important to remember that building an app is an iterative process and you may need to pivot your strategy as you go along. As a leading mobile app development firm, we're now investing our time and resources into developing world-class apps across other industries including health, education and food delivery.