When you make a comparison, you figure out how things are similar.
Making comparisons is about taking a look at characteristics or qualities that show the similarities between living things, objects, or anything else. In the supermarket, people make comparisons based on price and ingredients. Lots of essays and articles make comparisons: between different politicians, bands, movies, athletes, and even whole era. Many teachers ask students to write comparisons in essays. If two things are totally different, you could say "There's no comparison!"