I'm frequently asked for recommendations to consultants or service providers. I have a handful I've worked with or been in close contact with over the years.
Conversion Rate Optimization, Customer Experience, Design: Ilana Davis (yes we're related) - she finds where buying friction exists in ecommerce stores and adapts the current design to eliminate friction, usually without a full redesign. You can visit her website.
Marketing, SEO: Kai Davis (no relation) of Double Your Ecommerce - he's helped me a ton with more detailed SEO questions and we've worked together on numerous projects. He's more of a traffic and marketing consultant but has a solid background in SEO. Contact him at Double Your Ecommerce and mention me.
Theme development, Conversion Rate Optimization, Marketing: Kurt Elster of Ethercycle - he's a friend and colleague who does a lot of theme development, conversion optimization, and page speed improvements. Kurt's worked with top brands and has been featured by Shopify numerous times. You can visit Ethercycle to get in touch.