Shopify E-commerce Site Creation

I'm looking for an experienced Shopify developer to build a comprehensive e-commerce website. This site will primarily sell physical products and will feature more than 10 product categories.

Key requirements:
- Customizable and user-friendly design
- Intuitive navigation for over 10 product categories
- Secure payment gateway integration
- Mobile-responsive layout
- SEO-friendly structure

Ideal skills and experience:
- Proven track record in Shopify development
- Strong understanding of e-commerce UX/UI principles
- Experience with SEO and payment integrations
- Portfolio showcasing similar projects

Please provide a detailed proposal, including your approach and estimated timeline.