Methods to grow a fly
Five examples of ways to tie large flies. From top to bottom:
A: Simply tie in large materials (here hackle)
B: Parallel stacking, adding many short bunches of material to add volume
C: Tapered stacking, adding long bunches of material to add volume and length
D: Fanning, adding long material, but sparsely, to give the impression of size without too much bulk
E: Articulated shank, Using a shank to elongate the fly and create a larger fly without a larger hook
F: Pile-it-on, simply piling on materials until the fly looks (and is!) big.