focus: it depand your composition, any foregound subject?
shutter 1~2sec? sun already gone down liao.
RAW or Jpg, depand on your workflow.
important: know how compose your image, know how and where to take meter reading from and expose your image.
for me, I take meter reading around the sun but not including the sun, mostly shoot underexpose base on the reading, judging from the LCD to suit my taste.
Go to industrial areas, dust particles (pollution) in the air creates dramatic colours heh heh... Jurong island in the past was my favourite but now out of bounds. If you can find someplace around tuas am quite sure you will like the colours heh heh...