The Orton Effect (developed way back in the day for slide photography by Michael Orton) gives photos a dreamy, watercolor-like, glowy, soft focus appearance. I guess it used to be quite tricky and labor intensive to create. Fast forward a couple decades, enter the digital darkroom, and now it's just a simple one-click-action in Photoshop. Various Orton actions are available free as downloads. I like this one.
For those who don't have Photoshop, I know this effect can be replicated in Gimp (free online photoshop-like program). Just Google to find a work around. I know they exist.