I learned to ride in a cow pasture, and every time I feel I need to add a new skill I do it in an urban version of a "cow pasture" (soccer field).
Riding in the grass teaches you fabulous bike control, you really learn balance skills riding over the rough and mushy stuff. Asphalt feels like butter and so EASY after riding on a field. Falling over is no big deal in the grass (and I do fall over!) and you learn how to roll with the bike a bit to protect yourself.
It's silly, and it's fun, and I highly recommend it!
"If Americans want to live the American Dream, they should go to Denmark." - Richard Wilkinson