hi Alex, as well as the 'customer likes' tab on the app, it's also worth looking at the curated collection http://www.alamy.com/category/stockimo.html & the weekly 'grid of greatness' to get an idea of the feel & style of the collection.
I have found that my images tend to rate higher with subtle edits that enhance the mood of the image. Snapseed is a great 'go to' app, however, I find the 'grunge' effect is to strong for my taste & the hdr effect too grainy & garish unless significantly dialled back. I use Stackables for adding texture/grunge effects & VSCO for general editing & subtle filmic efffects. Enlight is also excellent. Not forgetting, of course, the native iphone app!
ann