If you haven't done so already, sign up on the Disney on Ice website and you'll get a flyer that allows you to purchase a few weeks before they go on sale to the public. I work for an arena and can tell you it makes a huge difference in your seating by doing that.
Also, generally the opening night of DOI offers a 1/2 price discount. Use that in combination with your presale codes and you can get really great seats for around $10. (At least in my area.. I think last year maybe $11 opening night?)