Any tips for a better responsive design?

Using a JS framework for this such as Knockout or React. Ensuring you use asynchronous calls were you can.

Use bootstrap or foundation.

Foundation and Bootstrap are old news.
I researched both of them for a new project idea, and I was about to use Foundation, but I came across some other info and changed my mind.
The rest of my story is in the README of my new repo: https://github.com/garrettw/vitals

In a nutshell: use Sass because there are flexbox frameworks written for it that will let you use your own semantic class names in place of "col-md-8" and such. Bootstrap, Foundation, and even Bourbon (which is written in Sass) are all float-based grids, so unless you need to support old browsers, flexbox gives you a lot more flexibility in your layout.

Think about the experience you offer on all devices, don't just cascade.

More @media queries