Here's a quick way to find out if your FB ad strategy is working:
Create an ad targeting post engagements. Add the best photos of your products possible.
Getting lots of engagement? Good. No engagements? Kill the ad and create new creatives/copy
If you get engagement, do a view-content/visit website target ad. If you get at least 300 clicks for a reasonable cost (ideal would be below $1 per click) then good... Create a lookalike audience and move to the next step. Otherwise, kill the ad and start over.
Create a final campaign targeting purchases. If you get a sale within profit margin, start creating lookalike audience. Otherwise, kill the ad and start over.
Edit: You can also try marketing your products with organic reach. There are a few useful strategies mentiond here: https://www.withintheflow.com/how-to-get-traffic-to-your-online-store/
How are you targeting on Facebook? Are you using the FB Pixel or defining your own audience?
Check out Pollen (https://apps.shopify.com/poln) for your Facebook ads. It helps you with setting up retargeting and prosepcting ads so that your ads always reach the right people. It's easy to setup and makes FB advertising simple and easy.
a must have that every store need to have is something to push people to complete the order, alot of people doesn't have some mechanism in place so their stats look like view product 1k, add to cart 400
reach checkout 200 purchase 30, sound this familiar? basicly alot of people leaving the website the most crushial time (when it's time to pay), something stop them maybe price or shipping, of course there are some apps that give coupons but most of them suck because 1 they give the coupon to early, 2 some apps require to change the link which is bad if you do advertising (essentially you need to change the adset link) now there is a killer app that convert more people on the spot you can find more at https://supersalesbooster.com