The most valuable metric in today's mobile-dominated world is consumers' attention. But the reality is that mobile feeds, such as Twitter, move quickly. The challenge for advertisers/marketers is to make a meaningful connection with consumers in a short period of time. As Tom Buday, the Head of Marketing and Consumer Communication at Nestle said in his talk during Marketing Week 2016, "The consumer will decide how many seconds they give us and we need to fit within that constraint. We are not in control."
In regard to the factors within a marketer's control, creative execution has the greatest influence on ad performance. According to Data2Decisions' two time published Admap report, creative execution is the second highest driving factor behind market size, and is shown to have about 10 times the influence of cost and flighting on ROI.
Optimal creative rely on best practices. There is a myriad of existing research from different industry bodies, and every platform, agency and advertiser has its own similar version of the fundamentals.