One of the first lessons you learn in school is to put a comma between your adjectives, just like I'm doing when I say I'm truly, madly, deeply in love with commas. I'm lying, but at least I'm grammatically correct. But here's the problem: that lesson is wrong. You don't always put a comma between your adjectives. You only put them between coordinate adjectives. With cumulitive adjectives, you don't. Yes, I'm about to explain what that means. Little Brown Ball You should always put commas between coordinate adjectives, which are descriptive words that are similar to each other. For example, if the painting is black, brown, blue and green, those adjectives coordinate because they're all colors. They all go together and fit in the same group. There is a simple way to test if adjectives are coordinating or not.