I've just recently learned how hard it is to capture rain and a sense of rain this well
Yes, it's not trivial. I shot a bunch of rain pictures last night, as well for the Rain II challenge. Back lighting is the best you can hope for to capture the raindrops. Otherwise, I found that setting the shutter speed to 1/60s (to smudge the drops) and the aperture to about f/8 (to have a deeper DOF to catch the drops) works best.
I love the wetness/rain here, great capture of that. One person walking like "ain't gonna get wetter than I already am", in the background the couple sheltering in the doorway of the shop, meanwhile the rain falling so clearly.
As to the contrast, you could use a selective color layer for that and adjust the black slider for the blacks and neutrals. Something like 'blacks' and 'neutrals' both to +14%. Personally I think it is already good as it is.
I absolutely love this photo. I've come back to it a few times now and each time it grows on me a bit more.
I agree with Germaine that there is room to punch this up a bit, I only wish I knew enough about post processing to tell you what I think would do that. Contrast might be just the ticket to make your darks darker and therefore stand out a bit more. I know playing with levels or curves in photoshop does wonders as well. I get accused of using my burning brush too much but I like the effect sometimes.
On its own tho.. I still very much adore this shot. It captures a moment we have all witnessed or experienced and brings you into that very moment.. the cars, the chaos, the woman rushing to get across the street, even the cheese sign are brilliant.
Thank you for sharing it.
~R~