I think you'll agree that your first two images are quite nice and that there is something a little bit 'off' about the last sunset photograph.
Many times you have to underexpose when shooting sunsets because the sun is so bright.
Also composition is critical for a good sunset photo.
Here some recent sunset images I've taken:http://duncan.photoshelter.com/gallery- ... UFJlH1_gF4http://duncan.photoshelter.com/gallery- ... St7sz76QUMhttp://duncan.photoshelter.com/gallery- ... BazFhfpV38
Always use a tripod and play around with your shutter speeds.
Use as low of an ISO as possible.
I like that you used golden hour in these images.
Be careful not to be too late in magic hour/golden hour though because you lose lots of light...
I'm happy with your progression through the course!