When Arielle Jackson started her career at Google, one of her mentors taught her to embrace the fact that marketing is a highly tactical function. To this day, she loves sweating the small stuff — mostly because it all adds up to be big stuff. That’s how she helped home WiFi startup eero pull in $2.5 million in sales in a fortnight via a successful pre-order campaign. All the little stuff — from the details of eero’s website copy to the subtleties of its customer communications — added up. Rainmakers are known for their storm, but Jackson pays mind to each droplet.