Prior to production Rachel Bloom met with a personal trainer who promised to get her ripped. Bloom decided against it, rationalizing that she wanted to portray her character as someone with an average body type. She also insisted on casting actors of all ages, races and body types to try to injects some realism into the show.
The writers only intended to use Valencia in two episodes, but everyone was so dazzled by Gabrielle Ruiz that she quickly became a series regular.
In order to justify the musical sequences, Rachel Bloom originally conceived a showbiz plot, with her character trying to break into Broadway. Co-creator Aline Brosh McKenna convinced her that it would be more interesting if Rebecca Bunch was merely a woman who envisioned her life as a musical.
Creators Aline Brosh McKenna and Rachel Bloom wanted the program to show that true, genuine friendships were possible with both the opposite sex and with people a different age bracket. The characters were written to demonstrate this throughout the series.
During the initial development at Showtime, creators Aline Brosh McKenna and Rachel Bloom mapped out a four-season storyline for Rebecca Bunch. A variety of changes occurred when the show finally went into production for The CW, but the overall plot outline for each season remained unchanged.