I use freezer paper as it adds to the accuracy and I starch the fabric within an inch of it's life.
Here's how it works for me.
I stitch on the line.
I then move it to a cutting board, fold the freezer paper back and cut a 1/4" seam with a ruler and rotary cutter. (If you cut it back with scissors there is a chance one of the fabrics will show through the other, but this is fine with medium and dark colours)
I fold the freezer paper back in position and flip over the piece I've just sewn on. Carefully I press this seam open.
I flip it back over and press the freezer paper on to the new piece of fabric. I love these little stick irons for this. I used to use a travel iron before I bought one.
When all the pieces are pieced I use the edge of the freezer paper and cut my 1/4" seam. Notice I haven't drawn my foundation with this seam included.

And here it is.
I won't remove the freezer paper until this unit is enclosed by other fabrics all the way round, or the top is finished. I use very fine thread and small stitches. Before I pull it out, I run the back of the unpicker along the seams, this pressure breaks the paper between the stitches.