This is not exactly photo editing but it is something I have been playing with since I did the altered canvas.
Sometimes there are photos that I like but that are a bit boring, or the colours are a bit off, or a bit blurry. If no amount of photo editing seem to improve a photo there is always the alternative to try to get an interesting result using filters. You need to experiment with the parameters until you get a pleasing result but it is really great fun and the results are worth it.
In PSE, you can find the Filters by clicking on Filters->Filter Gallery or, on the right hand side of the screen, under Artworks and Effects, choose filter in the first drop down menu, and artistic on the second.
Here's some before&after pics:
Watercolour Filter, parameters set to 10/2/2.
Coloured pencil, parameters set to 2/12/25. My favourite filter and one of the few ones that work well with portraits too.
Poster Edges filter, parameters set to 4/3/3. Very subtle change, but somehow it improves the photos by 100%.