If your conversion rate is less than 2%, you have the wrong traffic (not your target market) going to your eCommerce store.
To improve your conversion rate, you need a couple of things:
Make sure you have above the fold line what you sell and who you sell to so the person landing on your page thinks, "omg freakin' god, this website is for me".
And make sure your website pages load quickly. This is important for all website but even more important for eCommerce where you're chasing conversions.
List the benefits and not the attributes of your product offering.
Provide testimonials and perhaps a trust symbol like Google star ratings or TrustPilot.
Make the checkout process seamless. Offer all forms of payment options ... Stripe, Paypal, BT, Afterpay or if you're selling to Chinese, offer payment via WeChat.
Have an opt-in so people can sign up to your newsletter/promotional stuff ... because they might not be ready to purchase on the day they land on your website .... so it's good practice to nurture them through email marketing. I find Mailerlite easy and fun to use, especially if you want to segment your subscribers to make your emails more personalised. I suggest you send an automated email to ppl who place items in your shopping cart. Perhaps send them a coupon code in a couple of days. Make sure you add these people to your email list because they're a warm audience and your FB Ad spend is always cheaper for warm audiences.
You could also AB test your website whereby different versions of your website are delivered to different people and then you'll be able to see which one converts higher. Even something as small as changing the colour of a CTA can boost conversions.