When I think I have enough practice indoors, I'll pluck a heavily pesticided lime(not edible because of that) and try to sling it behind my house. The little lime sure won't do any damage to windows... I can't even stand with the proper way outside....
I have more confidence with my greek overhand, but not powerful enough to throw a heavier rotten mandarin orange.
Now, I noticed some risk at the place where I mentioned. Some cars may pass by my range without emitting any noise!
And the long grass there some more block my view for passing by vehicles. There is also a junkyard beside my range. Now, I don't know where to sling some rocks... I won't sling there again.