You know, you shouldn't always look at smudging as a purely abstract art. Give it a composition, something that makes it recognizable to the viewer, even just a little. What I like to do is start with just random smudging. One or two layers, whatever random colors I want and smudged in whatever way feels fun or good. Then when I finish that, I take a look and try to decide what it looks like - or what it could look like.
For instance, this piece:
You must login or register to view this content. . It started off as just being two terribly smudged layers of dark blue and light gray, and then I looked at it and thought it might look cool as a raincloud with lightning. Then you can work your smudging from there. Notice that there are four different smudge settings and styles that I used too, that helps to differentiate between different objects in the image.
Just a helpful little tip. =)