one thing that works well for me is to copy your video track and layer the copy over the original track. Then apply a blur to the copy track, usually as blurry as you can get it. Then use the opacity on the copied track to control how soft you want the image to be.....usually something around 25-30 percent seems to work well.
In the same sense you can apply any effect to the copy track to achieve specific looks, I like to increase the brightness to the copy track and use the opacity very lightly.....gives the overal look a glow.