Masking In A Sky ... It's All About The Details

I can't count how many times I've traveled off the beaten path for a landscape shot, only for Mother Nature to deal me a dull, bland sky. Fickle girl. But, all need not be lost. If the "bones" of the photo are there (to borrow a Karen Hutton term), substituting in a sky with character can rejuvenate the dull parts of an image.

The basics are easy and any tool that supports layer masks is all you need. However, it's the attention to detail that will ultimately yield success - color matching, angle of the sky, a smooth mask, and handling reflections. In this video, I show an example where I mask in a sky and handle a reflection in a still pool of water.

What tips or tricks do you have for masking?