Sometimes I like to do long strips of sashing and I will draw on the sashing where the blocks are supposed to go so I can line them up. However, if I am not in the mood to do all of the measuring (and if I am not putting the sashing between the blocks in the rows) , I cut pieces of the sashing fabric the height of the bocks and half the width of the blocks and sew it on alternating rows so the blocks are purposely off set. I do this mostly on row quilts or I Spy quilts (since the sashing gives the eyes a rest).