There are frameworks like Skeleton and Zurb's Foundation that handle the media queries and resizing/restyling for you, you just have to use their markup. And what they do out of the box is pretty much enough unless you want to hand-tweak a style down the road.
Also, responsive design doesn't have to be about getting your website to work on your 2001 Nokia brick's display. A good first step in responsive design is just to take advantage of the full width of the device your user is using up until a point. A lot of websites I view from my netbook could take advantage of just one media query: a full-sized design for large screens and then a fluid width design for anything smaller. I find a lot of websites give me a horizontal scrollbar on the 10' screen.
Also, responsive design doesn't have to be about getting your website to work on your 2001 Nokia brick's display. A good first step in responsive design is just to take advantage of the full width of the device your user is using up until a point. A lot of websites I view from my netbook could take advantage of just one media query: a full-sized design for large screens and then a fluid width design for anything smaller. I find a lot of websites give me a horizontal scrollbar on the 10' screen.