I used a hand piecing technique that gives a flat look to the front and avoids a lump of seam allowances all going the same way on the back.
To do this you sew the seam on the machine but stop at the place where the two seam lines intersect on each piece leaving the tip of the piece unsewn. When all pieces are sewn together press all of the seams clockwise (or counter clockwise). The important part is that they all go the same way around the circle. The points of each piece will make a star pattern. A little fussing with the points may be necessary when pressing.
The resulting flat block is well worth the extra effort.