The votes seemed to come in in batches. After all, 29 votes in total isn’t that much in terms of representativeness - so there is probably still a lot of noise going on.
On the topic of what influences votes (apart from technical quality), there are a few things I noticed over the last few weeks:
Adding text to the image seems to scare everyone away. So far, it never worked out for me. I guess an image just needs to speak for itself.
Keeping the eye close to the subject seems to help. If the main feature of the picture gets lost (to small, no contrast, bad focus, random composition, …) this will probably cost some votes as well.
A little story within the image seems to help a lot.