"Clean" isn't a word I would use for this work. To me this is anything but clean. I see a lot of fake lens blur, highlights, lens flare, etc. I'm not saying it's bad work. Just helping to define the term. "Clean" to me means free of distractions, blown highlights, and lost shadows, and sharp as can be. I think what you may be referencing is the contrast and/or saturation.
You can get there by either using actions found on the internet either for sale, or freeware, or you work with levels and curves and come up with something you like and save it as an action to repeat on multiple images.
One set I happen to be very fond of are the florabella actions. http://www.florabellacollection.com/
. I've created a few similar actions that I use on occasion but I don't shoot this kind of material enough to justify buying them.
I am serious....and don't call me Shirley.
Canon 7D and a bunch of other stuff