Theory:
We need triggers as reminders and to motivate us to take action.
Application:
Be where the people are and remind them of you, your company and/or your products or services. This can be on social networks, through advertising, newsletters, IM, SMS etc. People need to be reminded that your there and that you have a great product/service waiting for them. Don't be obnoxious, just gentle reminders.
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.