for the first picture, i pull the hue bar slightly to the right to make the blue stands out. but don't pull too much, cos the sky will turn purple.. hehe.
after that, pull the saturation bar to the right, and until your desired preference.
that's all!
for the second picture, i pull the hue bar slightly to the left to make the orange stands out. when the orange is desirable, pull the saturation bar to the right (not too much) until your desired preference.
as easy as ABC ya?