Organize your CSS as reusable components. Components are built up of parts (child elements), parts are included using __part-name. Components are flexible with options (like arguments; class="component-name --option). Tweaks are small changes applied using a + sign. You can watch a related Laracast here.

Refill is a collection of examples of web components you can use for Bourbon (Sass mixins library) similar to say, Bootstrap's components.