i find the lack of colors in the sky boring.
I think you need to check out some really good sunset shots as well as www.photoinf.com for tips on composition.
To avoid the danger of flat and dull looking sunsets the image needs perspective and a feeling of depth and distance. That means clouds in the sky, perhaps the sun in the photo, multiple colours and\or shades, and a foreground that is not too dark with some detail and relevance to the whole image...as in important detail and not clutter.
This is often best accomplished with a graduated neutral density filter as well as being at the right location at the right time since sunsets change very quickly.