Usually I don't edit much my landscape photos, not because I don't know how but I prefer them this way. Still, recently I felt the need for some more advanced processing for a picture, it enjoyed some success so I decided to share the process. The tools used were UFRaw (in the form of the GIMP plugin), Luminance HDR and, of course, GIMP.
I passed by this scene in the nearby park at the "golden hour" and it looked photogenic, but I wanted to make it more dramatic. One can increase the drama in a landscape photo by using a HDR treatment, but not having the tripod with me (for a proper HDR image you need at least 3 images with exactly the same scene but different exposures) I decided to go for pseudo-HDR. For this, I set the camera recording mode to RAW.
Note: the real purpose of a HDR image is to have details both in the shadows and in the highlights, beyond what the camera sensor can record, the improved drama is a side effect.
The RAW image was imported in GIMP via the UFRaw plugin 3 times: with normal, -1 and +1 exposure. If you really want, you can try doing the same starting from a single JPEG an simulate the exposure bracketing with color levels/curves, but I wouldn't advise: if from a RAW you can recover some lost image details, in JPEG they are gone forever.
The result is 3 JPEG images, one under-exposed, one exposed properly and the other over-exposed, which are to be combined in a HDR. For more drama, you can bracket with more than one step.
I imported the JPEGs to Luminance HDR and set their exposures manually to -1, 0 and +1 (or whatever values you used for RAW development). Then just press "Next" a few times, there is no need to adjust parameters, nor align the images (they were obtained from the same source).
Now we have a High Dynamic Range image, which can't be used or viewed as-is on a normal computer display, it has to be converted back to Low Dynamic Range, but optimized for what do we want from it (details in shadows and/or highlights, drama, whatever).
Time to pick one of the presets in the right column, one you think is the best for your case.
Then I adjusted the color levels a bit (if you prefer, the levels can be adjusted later with GIMP or any other image editing app).
Now the image can be exported as a JPEG benefiting from the HDR/pseudo-HDR treatment. You can leave it as-is if you like.
However, I opened it again with GIMP for more refinement: sharpening and color curves adjustment, to make the colors warmer. This is my end result.