First off, I would say you need to start with a good image right out of the camera.  This idea took my photography to the next level. I wanted to take whatever pictures I could and then go edit them in photoshop.  While this was fun and helped me to learn a ton about photoshop, it wasn’t until I took my technical skills seriously that I really saw a difference in my photography.  So, for an amazing sky you need to expose the picture properly.  I prefer shooting in raw now, but I didn’t when I was starting out.  I found that the constraint of a jpeg helped motivate me to get a better picture in camera.  Now that I think about it, that probably wasn’t the norm!

I have three examples of a sky that I enhanced in Lightroom. Here is the first one sooc (straight out of camera). 

This one is shot closer to blue hour. The sun was down, and it was already very dark.  In hind sight I should have had my shutter speed up and ISO up as well (since there is a bit of motion blur).  However, I was in a hurry because I was losing light. I still love the sky. So I do my regular adjustments first.  Then to enhance the sky I look at the colors that are already there. I use the brush tool, and I adjust the temperature and tint to give a more golden tone.  Then I use a soft brush to paint the areas where the light is coming through.

Next, I use a new brush to paint over the whole sky (carefully going around my subject).  Here, I increase the contrast, and the clarity.  I also lower the exposer and dehaze it slightly. After I have done that, I lighten the exposure of my foreground just slightly to make it look more natural.  You don’t want to go overboard with that part though.  It will not look right if you have a gorgeous sunset sky and a foreground and subject that looks like they’re lightened to be midday.  So just be careful with that part.  I try to make many small and subtle changes.  I don’t want to add what is not already there.

Here is the final image after all my adjustments.

In the second picture I have exposed properly for the sky.  Here is the image sooc.

After doing my regular adjustments I use the brush tool again and go over the whole sky.  I lower the exposure, increase the contrast, increase the clarity and increase the saturation.  I don’t often use the saturation slider as it can easily get out of control, but for this one I think it worked well.

Here is the final image after adjustments.

For this last one, I exposed for my subject.  Even though I underexposed slightly I still blew out some of the sky.

So, for this one I made my usual adjustments and then I went in with the brush tool.  I painted over the whole sky and lowered the exposure significantly. I also increased the contrast and warmed up the temperature/tint.

You could then see the rays of light coming from behind the clouds.  I decided I wanted to enhance that part.  So, I used the radial filter and put one right on top of the main light source (the sun).  I increased the temperature and the tint. Make sure that when you are using a radial filter that you click the invert button, or it will affect the entire picture other than where you put the filter. I use this often when enhancing light.

Here is my final image.

I hope you have enjoyed my tutorial! Please feel free to contact me with any questions you might have!