I have completed the elevation drawing and am now transferring it to my watercolor paper, which I have secured to my drafting table. I typically use 300lb Arches hot press for it's smoothness and I wont have to pre-stretch the paper due to its weight and thickness.
I have turned the trace drawing face down on to the watercolor paper and will re-trace the back of the drawing to transfer the image. Fortunately the building that I have chosen to draw is symmetrical so I don't have to worry about the image being drawn backwards. However, if your drawing was asymmetrical and you wanted the image drawn correctly in terms of how you actually see the building then you would have to trace on the back side of the drawing and then transfer. Or if you are feeling confident about your measurements and details you could draw directly on your watercolor paper with your pencil. I have been successful with this method but you have to use caution to make sure you use a light pencil and a light hand when drawing. Watercolor paper shows indentations very easily. Especially the thicker papers. If you have to erase you don't want to end up with ghost lines.