I had lots and lots of strips of different lengths and different widths. I sewed the too-short ones together. I had a pile of pieced strips and a pile of complete strips. I put them all together so that every other one was pieced.
A few places there is no pieced strip. I make sure that the join is not too close to an edge. If it was close, I cut it in half and found another piece to make it long enough with the seam closer to the middle.
I sew them all together in a big long row, but I make sure I always start at the same edge. When one edge of the row is straight cut the other edge straight with the ruler and cutter.