The whole trick of sewing a Mariner's Compass block is to start with
the smallest pieces on the outside edge and sew those to the smallest
point making larger wedge shaped sections.. then one of those gets
sewn on either side of the next set of points, and those wedges are
sewn to the next largest set.. and so on until you work your way into
the center.. the only tricky part I've found in the entire block is
sometimes setting in the center circle or octagon - and, worse case,
you can applique it on.. Also, I've always used separately cut corner
sections to square up the block rather than appliquing the completed
compass onto a large square..  Judy Matheson has a book on compass
patterns that is very good, both for patterns and for instructions..