For those who are a bit math challenged, use graph paper. Mark out a section for a yard of 40" (I round down) fabric.
Then mark out your pieces in it starting at one corner. Often we need to see it drawn out to have it make sense. As far as using it as LOF or WOF, do you ever use precuts? you don't usually know which way was which, so use it any way. I have even used pieces cut on an angle for the pattern. You just need to be extra careful of the stretch factor.