How do I get this faded, soft effect?

Honestly, it looks like a really ugly post-processed depth-of-field effect. Probably just did gaussian blur instead of lens blur. Then they masked out (or masked in) the parts they wanted in focus.

I wouldn't bother trying to mimic photos like that. Its like actively learning to put lipstick on a pig.

But if you MUST, it looks like they over-smoothed the skin, then selectively gaussian-blurred the top corners.

But seriously, it is a terrible, really bad no-good trend that is on it's way out the backdoor already.