Margaret Glaspy's mind is bursting with words and melodies — and she's pretty sure yours is, too. "Anybody can write a song, any time of day," she says. "It's in the air. You just have to sit down and work at it."

Sitting on the stoop outside her Manhattan apartment on a weirdly warm January afternoon, Glaspy, 28, recalls the rigorous work that went into writing her debut album, 2016’s Emotions and Math. For three or four hours a night, she recorded song ideas onto an iPad, through good moods and bad. "As human beings, our minds are totally on fire creating thoughts, whether we like it or not," the singer-guitarist continues. "From there it's just a matter of organization and filing things away. You get a good idea down, then you get some sounds, and then you leave it open so you have something to come home to tomorrow."

Emotions and Math is a remarkably focused album, full of acerbic riffs that punctuate sharply written scenes of twentysomething love and frustration. ("You don't know my situation / We've had at most one conversation / Don't come out of the blue and tell me what to do," she snaps on the chorus of "Situation.") Glaspy's songs don't meander, noodle, or hesitate; they get straight to the point and stay in your head as long as they like. You might catch an echo of Liz Phair, Jeff Buckley, or Elvis Costello, but Glaspy is original enough to elude a definitive comparison.

Her own point of reference during those late-night writing sessions was Elliott Smith, particularly the last album he released before his 2003 death. "Figure 8 was my bible," she says. "His harmonic vocabulary and his chord changes changed my life, for sure." She mentions "Everything Means Nothing to Me," one of Smith's loveliest and most despairing songs: "I remember hearing that and being like, Gosh, I've felt that way on several occasions. But you never want to say something like that out loud, because people would think that maybe you're a little depressed or a little crazy."

As a kid in small-town Northern California, Glaspy was schooled in the ways of rock by two older siblings. "My brother was totally in love with rock and roll from every angle — Deftones, Led Zeppelin, NOFX, Rancid," she says. "And so much Nirvana. And then my sister was obsessed with Beck, Lauryn Hill, Weezer ..."

After high school, she moved 3,000 miles away from home to study vocal performance at Berklee College of Music but had to make other plans when the arts grant she'd won ran out. "I dropped out when I had just turned eighteen, and that whipped me into shape," she says. She put in a few more years gigging around Boston before heading to New York. Once there, she babysat by day to subsidize her night shifts writing songs and performing at small clubs like Rockwood Music Hall, Cornelia Street Cafe, and Pete's Candy Store. "I played a lot of shows where no one came, and it's kind of heartbreaking," she says. "But when you know that you want to do it, you take those things as a green light."

She was nearly done home-recording a first draft of Emotions and Math when she signed to ATO Records in 2015, joining a forward-thinking, roots-leaning roster that includes Alabama Shakes, Drive-By Truckers, and Okkervil River. It's a good place for a self-described guitar nerd like Glaspy. "Guitars are who I am," she says. "It's not a cool instrument — I don't think guitars are on trend right now — but I don't care."

Her contemporary heroes are instrumental wizards like Wilco's Nels Cline, whom she also counts as a close friend. She got to know him through her boyfriend, Julian Lage, a jazz guitarist and frequent Cline collaborator; Glaspy and Lage spent this past New Year's Eve at home with Cline and his wife, Cibo Matto's Yuka Honda, geeking out over his extensive collection of six-stringed instruments, amps, and pedals. "Guitars were played," Glaspy says with a laugh. "I'm like a kid in a candy store over there."

When we meet, Glaspy is savoring a rare day off at home before heading out on her latest tour, including dates opening for Andrew Bird and The Lumineers. In addition to winning over new audiences, it's an opportunity for her to reconnect with mainstream pop music: Last year, she spent the long drives between gigs getting deep into Justin Bieber, Rihanna, and Drake. "It’s the hooks!" she says. "They shut down a negative, jaded part of my mind that gets really analytical about songwriting. And that's fun."

Lately, Glaspy says, she's been wondering how to evoke a similar feeling in her own music. "I don't strive to be Justin Bieber," she says, "but I do think about creating a space where people can let go and become another side of themselves." She mulls it over and grins. "Maybe that's the next record."