I learned a lot by doing this one. I never tried to create rain before, so this was fun! I was inspired by a previous contest to create snowy art. Maybe next time I'll do snow... hmm...
Source files:
car,
sky (hit return at address line, to view sky image, it's protected from cross-linking) and
umbrella... Oh! and
rain (on the lense). The other rain was made by noise and motion blurring, with select masking.
Let me know if this helps you at all with your chopping

Or, if you have any suggestions for me, please comment! Thanks!