There was an article written a number of years ago by Michael Orton in Popular Photography about a technique he was using to create a soft romantic, ethereal feel to his photographs. He did it by stacking slide film of different exposures to create an image that was more like a painting. Nowadays we have digital pictures and the means to simulate the effect in Photoshop and other programs. It's worth learning and experimenting with.
I have seen other methods, but I'll describe mine as used in Photoshop 7. Some of the names of processes may be different in your programs, but I think most will do it.
My method: Open your photo and save as another name. Always keep your original. Duplicate the layer, then lighten the image by going into Image, Apply Image, then picking Screen from Blending mode, set to 100%. This approximates an overexposed image. Duplicate layer. Now go to Filter, Blur, Gaussian Blur, set Radius setting anywhere from 15 to 50 pixels. You can easily go too far with this, the example above was 50, 25 to 30 is often enough, play with it yourselves.
Next step, either by opacity or transparency, set the level on your top layer where you like, at 70 or 80% at first, tastes will differ according to image. From here you have the choice whether to do this with two layers or three. The example was two, but I've done it both ways. For two layer, you can get rid of the bottom layer and Flatten Image, for three, you can set a semi transparency on the second layer as well and flatten all three, which will darken your image somewhat.
Try the two layer and three layer methods and see what you can come up with.