Digital Diva here. My new favorite iPhone app is Ezimba. It contains so many permutations to create photo art that I can't remember which ones I used where in this group of photos except they were under the category "Artistic Effects". No matter, just open up a photo and app away. One clue - when you apply an effect, save it, and then undo before applying a new effect or it will just continually layer effects. Unless that is what you want to do - there are no rules. Ever.
The first photo is straight from the iPhone with no tweaking - it's pretty good just as is.
These next three photos have Ezimba effects applied.