Like my other Instructables, I will include DAISNAID notes (Do As I Say, Not As I Do) so y'all can end up with something better than me if you were inclined to give it a shot.
Much of my approach has been inspired from Featherweight's pictures at Cosplay.com. Check him out. I promise you his stuff is a helluvalot better-looking than mine :-)
Step 1: References and templates
A document was then created in an image-editing program with a canvas size big enough to accommodate the prop. Then a reference picture was imported into a new layer and scaled to the proper size. The sword was then traced on yet another layer. Once that was done, the reference layer was hidden and the line art was duplicated several times. The original line art was then hidden and the duplicates were modified, erasing different parts, to create the different pieces that would be needed. The layout was then optimized and printed out. It wouldn't all fit on one page, so everything was carefully lined up and secured with masking tape.
A large piece of corrugated cardboard was found and sprayed with an adhesive and the printed template was stuck to it. After a few moments to allow better bonding, the individual pieces were cut out using a box cutter. Some of the smaller pieces were cut using scissors. Essentially, these would be the bones used to make the skeleton in the next step.
Now before anyone asks, the measurements and the templates used will not be made available. There's alot to be learned in the process described here and I believe the reader will gain more value by going through the experience themselves. Everything you need to know has been written here :-)