At age 18, Kirsten Green sold women’s clothes at the Nordstrom in Walnut Creek, Calif. Twenty years later, the retailer backed her fund, Forerunner Ventures. Green, 45, has made a name by investing in a handful of e-commerce supernovas, including razor-delivery startup Dollar Shave Club, which was acquired by Unilever in 2016 for $1 billion and e-commerce marketplace Jet.com, bought by Walmart (wmt, -0.90%) for $3.3 billion.

Green started as a retail analyst and always felt “safe in numbers.” Eventually she took more risk and in 2002 invested in a little-known company called Deckers Brands, which owned Teva sandals and had acquired a boot company called Ugg. Within a year, the stock went from $2.50 to $42 per share.

Green was new to Silicon Valley, so she did research…