Use SASS with partials and mixins and sort them as it's more convenient for you (probably following the natural flow of descending order of your page).
SASS has helped me with organization tremendously. With SASS I keep a "typography" partial that is the basic text elements (h1, p, etc.) and font-family variables.
I also have a "colors" partial where I put variables for all my color definitions, such as $light-blue, $dark-gray, and $background-color.
