React Native App Responsiveness Optimisation

My React Native application requires a thorough optimisation to improve its responsiveness across both iOS and Android devices. The areas of concern include user interface interactions, data loading processes, animations and transitions, as well as the background file upload process.

Key Requirements:
- Extensive experience with React Native and optimising mobile applications
- Proven track record of improving app responsiveness
- Familiarity with both iOS and Android device specifications
- Ability to enhance user experience without compromising app functionality

Please provide examples of previous similar projects you've completed.