Steve: Your watermark is too large and too brignt. It should be in the lower right corner. It was the first thing my eye was drawn to when I viewed the image in download.
I would 2nd the idea of trying a black background. Also work with your exposure. On the posted image the white background is coming gray, which I sure not what you are going after.
Some excellent advice here. Keeping working with it. You will get worked out.