A quick way to tell which colors look good on you is to simply think about which colors look best on you. I mean clothing. Some colors will wash you out, and some will look great on you even if you don't like the color.
One thing that annoys me about the makeup industry is that they define pink/red undertones as cool even though they're technically warm. Yellow/olive as warm even though they're neutral, and blue/purple/green undertones as neutral even though they're cool... fashion and art professions disagree with you makeup professionals! This isn't like concealer where you counter-balance your tones.
Anywho. If let's say pinks and peaches look nice on you, you have pink/red undertones to your skin therefore in the makeup world, would wear a cool tone I guess... If cool colors like purple, blue, and green look nice on you then you have purple/blue/green undertones which means you would go for neutral lip colors. And neutral colors would be warm lip tones.
Also, the fuller your lips the lighter a color you want to go with except in cases of red. Then just stick with the undertone guide.
Here's a look at some brown colors. See how some of them have more of a cool purple color, while others have a more yellow/gold tone? And then others have a warm rose-y color to them.