Planning and patience
Planning is the most important thing, I would recommend going to the location around 30 minutes before the start of the sunset to compose your shot, especially if you don’t know the location.
With sunsets, the scene can change very very quickly. I highly recommend composing your shot, placing your camera on the tripod, and not moving until the sunset is totally finished.
Sometimes a nice color can appear on a cloud for only two minutes, and if you’re not ready then you won’t be able to photograph it. There is an app called Magic Hour which you can download on your mobile device (for iOS only) Based on your location, it will give you the time that magic hour begins, the time of the sunset, and the time it ends. It also does the same thing for the sunrise the next morning.’
With this information, you have the time to look around, try different compositions, and decide which one works best. I will repeat – once you find your composition, place your tripod, and do not move it. It’s better to have one good photo of a sunset then five different average ones.
You will stay behind your tripod for 30 minutes, taking an image every time the sunset changes, with the clouds moving and new colors appearing. It is quite frustrating, but at the end you will have the best composition possible, with an image of the best clouds, and the best colors of the whole evening.
I waited in the cold for one hour to photograph this sunset. At first it looked terrible, but it started developing very well. I ended up having some nice cotton candy looking clouds.