Adobe Lightroom Graduated Filters How To
Please, whatever you do never overuse this tool. Use it lightly and to taste. A little goes a long way!
That said I do use graduated filters a lot especially for outdoor photos. Sometimes its just to slightly darken a bright white sky because I was shooting during an overcast day or other times its to deepen a blue one. As you also notice the last photo I used a graduated filter on a product photo to edit out a few spots in the photo instead of using the spot tool or clone stamp in Photoshop.
The coolest effect this tool has is the color picker. It can enhance a sky and give it a soft color shift that suits your vision of the final photograph. You might need to try a few tones until you get the best one, but that’s where snapshots and virtual copies come in really handy!