So far, the first season of Supergirl has focused on Kara Danvers' transition from Cat Grant's assistant to National City's resident superhero. She's got the costume, the nemesis in her evil Aunt Astra, and the attention of the country (as well as its major news publications). Both within — and outside — the show, many have discussed why it's important that Supergirl is a female hero, but what of Kara? If you think that the everyday woman isn't as strong as her superhero counterpart, then you're completely wrong.
Like many heroes before her, part of Supergirl's strength lies in her relationships with the people in her regular life. (Remember Buffy's Scooby Gang? Sidekicks in general?) Where would Supergirl be if Kara wasn't already friends with Winn Schott? Probably flying around National City without a superhero outfit, tossing her glasses into dirty alleys and ruining cardigans willy nilly. Similarly, James Olsen offers Kara friendship mixed with mentorship (mixed with a little bit of romantic interest, but we'll see how that goes) because of his connection to her cousin, Superman. He's a friend/mentor/maybe-love interest who has become a useful ally for Supergirl as well as Kara. Winn, James, and Kara recently formed Team Supergirl and they seem to make a formidable alliance of friends who help Kara fight villains and in her day-to-day life.
As for Cat, Kara's boss has consistently challenged her worldview, specifically Kara's derision of the word "girl" when she became Supergirl. Cat's pro-girl speech, along with other moments in which she has challenged gender stereotypes (like pointing out that women need to work twice as hard as men in most jobs) or offered advice (starting small and working your way up) have had a significant influence on Kara, and in turn Supergirl.
That being said, Kara's strongest relationship is with her sister Alex, who went from wanting to protect Kara from the life of a superhero to teaching her younger sister how to hold her own against the villains of National City. The two grew up together and Alex became Kara's best friend as well as her sister, giving her all the support needed to be a superhero, or simply pick out an outfit for a first date — Alex can't be faulted if the guy turned out to be all wrong for Kara.
However, Kara's biggest strength lies within herself. I know that sounds cheesy, but it's true. Not everyone has what it takes to be a superhero. Even with all the training in the world, someone may not have the heart or the strength to put others' interests before their own, to want to help those that can't help themselves, or to get up even when your opponent is stronger and more skilled than you. Kara, however, has all these attributes in spades. She may have the alien powers of Supergirl — the flying, the heat vision, the cooling breath — but Kara finds her greatest strength from those around her, as well as her own character.
Images: Darren Michaels/Warner Bros. Entertainment Inc.; Giphy