How to post-process underexposed sunset images?

I am a beginner, given an advice to underexpose when shooting sunsets. I did, and, well, what was underexposed, kind of looks underexposed. Can I tease out any more out of my material? My camera does not shoot raw. The best I could do was to shoot the largest files it would record. I know I can open them as "camera raw," but right now I don't really know how to operate in this mode. Moving things here and there intuitively does improve some of my images, however. I would like to master this mode (i.e., when a jepg. file is opened as "camera raw" in PhotoShop) to the extent it is possible when editing jepg images. Specifically, underexposed sunsets. Here is a link to one of the images I would like to improve. http://www.flickr.com/photos/96576146@N06/9063908406/in/photostream

Answer

The motivation behind the advice to under expose sunset is that the sun and the sky are very bright and you get more detail in the sky and better looking sunset if you underexpose a little.

Also, because of the brightness difference between sky/sun and whatever is in the foreground if you expose for the foreground the sun and sky will be very over exposed.

The trick isn't to just under expose it's to expose for the sky, completely under expose the foreground and set the exposure so that the sky looks good (usually under expose just a little bit compared to what the camera say is the correct exposure for the sky only).

But there's a second part for this "trick", now you got a good looking sky but your foreground is basically a silhouette - so you add light to balance the foreground exposure with the background exposure.

Your camera's built in flash probably has the power to light a single person at close range but the light isn't going to look good, an external flash placed off camera will give great results for one person and can probably light a small group, to light a building you some serious studio lighting equipment (or a lot of small flashes) and lighting an entire street like in you photo is basically impossible.

So, your options are:

1. 
   

   Expose for the sky, let the foreground drop into darkness, maybe make it a silhouette.

   
   


2. 
   

   Take two pictures from the same exact location (use a tripod), one exposed for the sky and one for the foreground, use your favorite image editor to combine both.

   
   


3. 
   

   Take more than two pictures and use HDR software

   
   
   


4. 
   

   Start playing with flashes