Cutting fabric // Cutting paper

Dear users and authors,
do you have any tips and tricks for cutting fabric, paper, or craft cardboard?

When cutting fabric, make sure the grainline runs correctly; with printed fabrics that have a large repeat, be careful that the pattern doesn’t shift and fits perfectly; include the seam allowance (SA) when cutting; with checkered fabrics, make sure the checks line up and don’t run off-pattern on bags, etc.
With knits, make sure that when the fabric is doubled, it lies exactly in the direction of the stitches; otherwise, the side seam will twist toward the front afterward—it’s better to cut it out in a single layer.

For paper, I use this cutting ruler (plastic) that comes with a built-in cutting blade, or rather a rotary blade (you can slide it back and forth, remove it, and swap it out), and I also have two extra cutting blades for wavy cuts, straight cuts, and perforated cuts.
It works great for long, straight lines—you get a nice, straight edge, which is also perfect for photo borders.

Thanks for the info.
Does anyone else have anything to add?