Today, pick a work of fiction or non-fiction you’ve been working on and read through it (or a chapter of it if it’s a long piece). Try to list out the various assumptions you’ve made. You’ve assumed the protagonist must make a certain choice. You’ve assumed your reader will care to know only a certain subset of information about your subject. You’ve assumed readers of your how-to guide will tackle their projects in a certain order. You’ve assumed your readers will only come from a certain age group.
Change those assumptions. Substitute new ones. Reverse them. Brainstorm alternatives. Then re-write your piece with those new ideas in mind.