For whatever reason there are a ton of “guru” types in the ecommerce world. Some have legitimately experienced success, others are faking it. Still others have gotten lucky with a hack and now are trying to sell that hack to you.
You need to learn to evaluate what these folks are selling / saying and then think for yourself. Here are a few things to keep in mind:
every store is different, what works for one might not work for the other
the product is more important than just about everything else
competitive positioning is very important
not every product is suited for every channel
things change quickly, what’s working today may not work in the future
beware of fads like Free Plus Shipping
Ultimately your efforts are best focused on building your brand and your customer list. If you figure out some hack that works milk it for as long as you can but remember things change and be prepared to pivot.