We remember things better when we have experienced them through multiple senses.
Our memory is used to experiences containing information through multiple senses, because that's what happens in the real world. Sadly, as a website owner you can only use a very small subset of senses. Smell, touch, taste, temperature etc. don't go through an internet connection very well, so you have to make sure you dó use the ones that are available: sight and hearing (and some might add humor). Add images, audio and video to let people experience your products and to augment the claims you make in product descriptions.
Recently I've seen some (often absolute) statements going around, generally in the line of "open source commerce platforms are a terrible idea". Now of course different solutions always have different pros and cons.
A hierarchy of evidence (or levels of evidence) is a heuristic used to rank the relative strength of results obtained from scientific research. I've created a version of this chart/pyramid applied to CRO which you can see below. It contains the options we have as optimizers and tools and methods we often use to gather data.