Things that stand out attract our attention.
The most important elements on your website should stand out. You can use several design elements (color, shapes, movement) to create a (subtle) pop-out effect. You can also use this effect by deviating from your regular routines or style by providing unexpected content, movies or newsletters.
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.