Responsive Design, Always
I also build websites with responsive design in mind. Responsive templates, made for all screen sizes, are recommended for SEO and we know that Google is in the process of migrating all websites to its Mobile-First Index.
Every site I build is also inclusive of core on-page SEO elements including title tags, meta descriptions, alt tags for images, page speed analysis and proper internal linking. I run every new build through Screaming Frog and also include tracking for Google Analytics / Google Search Console. My clients are guaranteed a well-made and SEO-friendly website when they work with me.