Well honestly, I always save a new color when I make one. It's pretty important. It takes a lot of playing around with the color palette. What you could try is use a satellite image overlay.
Cool trick I've learned. When you use a satellite overlay, it is a bit dim. First, get a good ground color working, one that will be good for the whole map. I can spend 10-15 minutes trying to get that right alone. Once you've figured that, find the colors for a runway or something. Usually, some shade of grey is fine. When you put a polygon, such as a runway, down on the overlay, if the color is right, it will look just like it should. I hope my explanation is understandable. If not, observe:
Notice the darker green areas are where I've input a polygon with a dark green representing trees. You can also see the areas where I have not put anything down yet besides the ground color. When you have the correct color, it should highlight the area and make it come to life. The colors aren't perfect, but as you can see, they get down to the point. You will always have to adjust colors when you have a different scenery. If I go to Nellis and try the same color for trees, it may not work there because of the environment.
I have a huge collection of colors at my disposal and I tend to recycle them a lot, which when I release some new maps, you might notice the same colors. These colors are like my fingerprint, my signature. I would like to share them, but I feel that it is better when someone can make their own colors. It's like artwork and everyone will have their personal touch.
All in all, what you should do is develop your own colors and most importantly, SAVE THEM. Back them up, do not lose them because they will save you hours of time and effort. Always expand your collection. If you get stumped, you can go to a similar map, pick up color, and then save it, modify it, and use it. The internet can also provide you RGB and HEX codes that you can use. Scenery editor does not translate HEX codes so use something like paint to get your RGB values.
Hope this helps
