Heavier Fabrics Add Volume
Heavier fabrics add volume to a thin frame, whereas lightweight fabrics have a drape that accentuates a thinner frame. It's a good idea to go for heavier wools that hold their form. This body type is not limited to just heavy wools; light colored cotton or linen would also work.
The black bow tie defines an entire style, and as such deserves a bit of respect. Pre-tied and clip-on models are simply out. A fixed-length tie of a length appropriate to your neck is always preferable to adjustable models as well; the latter will have excess fabric that doubles over and adds an unsightly bulge to the knot when tied. To keep the tie proportional to your face, try to make sure that the ends of the bow fall somewhere between the edge of your face and the outer corners of your eyes -- anything smaller will make your head look oversized. The material of the tie should match the jacket's lapel facings visually; shiny ties with soft-fronted lapels will create a glaring breach of the outfit's uniformity.