Create a new emoji character. Go through a brainstorming process to come up with useful new emoji types. Design them, in the style of different emoji / OS alphabets (Google, Twitter, OpenMoji…).
Study the emoji submission process:
Get inspired by actual emoji proposals : https://www.unicode.org/emoji/charts/emoji-proposals.html
Get inspired by the OpenMoji styleguide:
Related reading: Ellen Lupton, Design is Storytelling, p. 100.