If you are matching the design, you can lay the first strip onto the fabric in the exact place.Be sure the design is matching on both fabrics and then cut the second, third, or forth strip. Use a marking pen and mark the bottom fabric to show where you should make the cuts.
If you are matching backing fabric allow for the seam allowance. I use 1/2 inch seams when seaming backings.
I also use a sticky note with an arrow to indicate the up or top position of the fabrics. It is easy to get them turned when sewing them. Yes, to cutting on length of fabric. I always cut borders that way. Plus stay stitch around all borders and then press again. Stay stitch around the quilt edges and press again. Then add the borders onto the quilt. Hope that helps.