I used to struggle to think of ideas what to draw, so just like the post sais above I walked around drawing many standard objects. Once I felt I was doing enouhb of a good job with angle, shade and perspective I began to mix them together.
my style is very unique, usually blobby and grotesque dribbling critters
when I was younger ( well I still do it ) I drew many old country farm houses, half fallen over, water tanks etc.