Should I A/B test different email templates?

I've been running my Shopify store for two years now, and while our product lineup is solid, our email marketing feels like throwing darts in the dark. We send out weekly newsletters and promotional emails, but our open rates hover around 12-15%, which I know is below industry standards. I've heard about A/B testing from some e-commerce forums, but I'm honestly overwhelmed. Do I test subject lines? Body copy? Button colors? Images? And more importantly, how do I even set this up without hiring a full-time marketing specialist? Our email list is growing—we're at about 5,000 subscribers now—and I feel like we're leaving serious money on the table by not understanding what truly resonates with our audience. I want to be strategic, not just randomly changing things. My gut tells me there's a systematic way to improve our email performance, but I need a clear, actionable roadmap that doesn't require a computer science degree to implement.