Having been processing lots of sunset shots recently as well as being asked to comment on those shot by others I thought it would be an idea to put together a list of top tips:

1. Use a Tripod. This is an obvious one but I find its best to start with the obvious. I have seen quite enough images which have been shot hand held because the camera exposure was fast enough to hand hold. Unfortunately the camera was giving the wrong exposure reading. Use a tripod and forget about hand holding.
2. Use ND Grads. Whilst there are possibly a few situations where you won’t need to use a grad, make your starting position that you will be using ND grads to darken the sky. A common problem when shooting sunsets is that the camera gets confused by the bright sky and tends to underexpose the foreground. The ND grads can help correct this problem by darkening just the sky. Also don’t be scared to use two grads together if the difference in brightness between the sky and ground is sufficient to warrant it.
3. Check your exposure. Ensure you get the exposure for the foreground correct then seek to hold back the sky with ND grad filters. Whilst it is possible to pull back detail in shadow areas if you shoot in RAW, it’s usually noisy and has poor definition when compared to a shot that have been correctly exposed. If you shoot digitally check your histogram after each shot to ensure this. If you find you can’t sufficiently grad the sky, consider taking multiple exposures and then combine the two images in post production (much easier if you use a tripod). Its time consuming but well worth it.
4. Seek out water and reflections in your sunset images such as wet sand and rocks. This gives life to your images as sunlight reflects off these surfaces. It can also help to balance out the difference in light levels between the sky and ground.
5. Composition. Composition. Composition. When seeking to shoot a great sunset it’s easy to just focus in on the sun and great sky. This leads to boring images that people tire of quickly. Ensure you include something other than the sky; basically foreground interest.

I could keep going but rather than drown people in information I would ask you to practice and master just a few points out in the field. When this becomes second nature then learn some more. It’s funny how most people know most tips yet few practice them out in the field. Those that do tend to be the ones that produce the best work most consistently.