I was on vacation a few years ago at a resort in the Caribbean. Each evening as the sun began to set people would gather on the beach to watch the sun go down over the ocean (for East coasters this is a fairly unique experience). I was sitting on the beach enjoying the sunset when I noticed out of the corner of my eye a flash going off. I turned to look and saw a man with a Canon Rebel pointing his camera at the sun and ripping off shots with the integrated flash firing. Suffice it to say the camera was in AUTO Mode. I figured that this was a good subject for a GetOffYourA blog post (or four).
So here is the short answer (and this is a matter of preference); more detailed answers follow.
We want an UNDEREXPOSED SHOT - the sun will be powerful - we want the soft colors
0 - Remove filters - take off your sunglasses - TURN OFF THE FLASH
1 - Switch Aperture Priority Mode
2 - Open Aperture to F5.6 or higher (don't worry about depth of field you are focusing deep)
3 - ISO to 100-200
4 - Set to Point Focus
5 - Focus on the horizon, but not on the sun - go for a nice color point
6 - Recompose (move the camera before exposing) such that horizon is at the bottom third of frame
7 - Shoot
8 - Evaluate the screen AND histogram
9 - Go to Manual Mode - keep Aperture setting the same
10 - Raise shutter speed (some say by factor of 2) - if Av yielded 1/200 then set to 1/400
11 - Recompose (move the camera before exposing) such that horizon at the bottom third of frame
12 - Shoot
13 - Evaluate the screen AND histogram
14 - Throttle speed setting to your liking
15 - KEEP SHOOTING - the light constantly changes as the sun sets and the colors are amazing
16 - Try again tomorrow