How can retargeting ads on Facebook or Instagram remind people about the items they left in their cart?

I've been running a fashion accessories store on Shopify for three years, and cart abandonment has been my constant nemesis. Every month, I see hundreds of potential customers adding items to their cart but never completing the purchase. It's like watching money slip through my fingers. My Meta ads are driving decent traffic, but conversion rates remain frustratingly low. I know these shoppers are interested—they've already selected products—but something stops them from checking out. Maybe they got distracted, were comparison shopping, or needed more time to decide. Whatever the reason, I'm determined to bring them back and close the sale. I've tried manual retargeting campaigns, but they feel scattered and inefficient. I need a systematic approach that not only reminds customers about their abandoned cart but does so in a way that feels personalized and creates genuine urgency. The goal isn't just to remind them, but to provide a compelling reason to complete their purchase right now.