The song was written and produced by Ariel Rechtshaid and Justin Raisen, with additional songwriting provided by Ferreira and Daniel Nigro.

Ferreira explained that her life was essentially limited to modelling, crafting songs and "watch[ing] TV", which resulted in her not having a "chance to discover [her]self.

[9][10] Ferreira stated that she conceptualized the track as a "super-poppy version" of David Bowie's eleventh studio album Low (1977); she was told that the song itself resembles the works of singer-songwriter Siouxsie Sioux.

[11] Its instrumentation is marked by the mixture of pounding, "crude" percussion and electric guitar riffs, accompanied with "tinny six-stringer scrapes".

[15] The songs' lyrics were written by Ferreira, Rechtshaid, Raisen and Nigro; they depict a relationship in which two love partners do not express sufficient mutual interest, due to the fact that they do not pursue each other.

[2][11] The Washington Post's Lavanya Ramanathan dubbed the song a "breakup tune" and wrote that in it, Ferreira embodies a teenager with "guy problems".

[16] For CMJ, Brooke Segarra billed the track as a "sexually assertive" number and interpreted the song's lyrical theme as listing the "mistakes and shortcomings" that come "with sex".

[20] Writing for magazine Spin, Marc Hogan echoed praise for the song—he described it as "impressively catchy and emotionally communicative" and also said it was "the type of track that might inspire a label to green-light—finally—her debut album".

[23][24] The official music video for "You're Not the One" was directed by Grant Singer, and written and co-produced by V magazine senior editor Patrik Sandberg.

[3] According to Singer, the video took nine months to craft; it was originally supposed to be filmed in Berlin so it had a "Christiane F. vibe", however this did not occur due to unknown reasons.

They reencounter in a black room where Ferreira sticks an ice pick on his face; in response, he slaps her, to which she smiles and they start kissing again.

[33] Dressed in a leather jacket, shades and with her hair wet, she was praised by Ben Kaye from Consequence of Sound for her "dazzling rendition" of the song.