This HBR article was originally published in 1982. However the findings are as relevant now as they were 37 years ago. 

The authors shared these three findings: 

1. Identifying the actual decision maker is not as easy as it sounds.  Power does not always correlate with organisational position. The authors describe how there are actually five bases of power and provides six behavioural clues to uncover who the real decision maker is!
2. Identify the way in which buyers act in their self interest.  It is a fact that buyers act selfishly. The article shares techniques to determine a customer’s motivation. 
3. Gather and Apply Psychological Intelligence of your buyers.  These three proposed changes should be implemented: a) make sure that sales calls highly productive and informative, b) listen to your sales force, c) reward regorous fact gathering by the sales team.  

I support these findings because I can see how startups can capture significant value from these practices.