I think that now that they have changed search to Relevancy it doesn't matter when you post....it matters what words you use in your titles. I put lots of words in my titles, like this one....Pittsburgh Cityscape Art Print, Digital Photography, Cityscape, Heinz Hall, skyscraper, EBSQ, 12x17. I think you want as many searchable words in the title as you can get. The more specific ones are first. Not sure I am explaining this well, because I only vaguely understand it.
I rewrote all my titles a while back. Not sure if it is helping or not...I have had no sales...:(
Carolyn