Vision is the most important sense and most direct way to perception through a computer screen.
Let your customers see your products! Use (professional) images that make your products look at their best. Or even better: use video! It's the best way to stimulate the brain and evoke an emotional response. Use images to replace or reinforce text or to make literal of suggestive associations. Even if you don't have physical products, you can show screenshots or a video about using the product.
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.