Habit Tracker App Graphics Design for App Store.

I need professional and clean app store graphics and screenshots for my Habit Tracker app.

Requirements:
- Modern and minimalist design
- iPhone (retina) and iPad resolutions
- Highlight unique app features
- Include user testimonials and reviews

Ideal Skills:
- Graphic design expertise
- Experience with app store graphics
- Ability to create engaging layouts
- Familiarity with iOS design guidelines

Please provide a portfolio with relevant experience.