According to this research by McKinsey, a customer narrows down their options based on the initial consideration (brand awareness) and active evaluation (seek information about the products/services). When both of the former factors are in place, it leads to a purchase decision a.k.a sales, albeit just for that moment. This then needs to continue towards the next stages in the sales funnel, .i.e. customer engagement and customer loyalty.
sales funnel history
In brief, we are inclined to go along with someone’s suggestion if we think that person is a credible expert (authority), if we regard him or her as a trusted friend (liking), if we feel we owe them one (reciprocity), or if doing so will be consistent with our beliefs or prior commitments (consistency). We are also inclined to make choices that we think are popular (consensus [social proof]), and that will net us a scarce commodity (scarcity).