My cousin is a pro and he does a lot of outdoors work, particularly tropical scenes. He always gets the greens and blues postcard perfect - not everyones cup of tea mind you but as he says, it sells heaps! How does he do it? His secret instructions, just for you and no-one else, go something like this (and they work OK for me) ....

bright/cont
selective color
-red - yellow to right
-green - yellow to right, cyan a bit to the right (brings out greens)
-yellow - yellow to right, cyan a little to right (brings out the greens)
-cyan - yellow slide to left,cyan slide to right,black a little to left (enhances the sky)
-blue - yellow to left, cyan to right, magenta - a little to the right, black a little to the left (enhances the sky
-white - black to left or right to increase any white brightness
-neutral - +3 to the right
-Black - +2 to the right
hue/saturate - increase as needed
match color - increase liminance
sometimes you may need to select certain areas of an image to further enhance but normally the above does the job

the amount you adjust the slides above depend on the image