Going mobile first, you start out designing big and tight. With desktop first, you will have to decide on what gets to stay and what has to go.
This approach uses the site's content strategy as a foundation, and helps me keep that strategy in mind throughout my design process.
By understanding the context, motivations, and desires of the person using the product, I can better determine how to design the details.
In this post, I want to discuss some concrete ideas about how a wireframe should be built in order for it to be useful.