Refine Android App Visual Design

My Android app’s screens are in place and the core flows work, but the visual layer still feels unfinished. I already have partial mock-ups that outline the layout, colours and components; what I need... (Budget: $10 - $30 USD, Jobs: Android, Figma, Graphic Design, Icon Design, UI / User Interface, User Interface / IA, UX / User Experience, Visual Design)