When we can, many of prefer to cut our long cuts along the length of the fabric instead of the width because of how the fabric reacts. Just like bias (cut on the diagonal) does some things, length- and width-wise fabric also behave slightly differently from each other.
Some times, like with an actual stripe (especially something like a wide Jinny Beyer design), you've got to fussy cut. Just no other way really around it.
Otherwise I prepare my fabric as I usually do, that is I prewash and press. Instead of folding in the standard manner, I fold the fabric along the selvedge, using it as my guide, including pinning together in the selvedge along the outer edge if necessary. There is usually a point in the folding where instead of folding in half, you go in thirds and call it enough. Smooth everything out neatly, keeping everything as equal and straight as you can. I usually sort of layer the fabric so the folds nest inside each other, that is, the biggest piece is on the bottom, the next side starts in an inch or so, repeat like an accordion.
I will make two cuts (two borders), then refolding the fabric from the other side, do the other two.
If I have to do more than four, again I refold what is left and smooth trim the outer sides and cut from there.