I strained my hand in February this year and started working with my left. It was a lot of practice and there's still plenty of that to go. But in the end there came some pretty decent drawings from it.
Here are some from our layout assignment Bonnie & Clyde this spring.

A small sketch












A bigger sketch

I also practiced croquis with left hand. Painfully slow and shaky at first but they got steadily better.
These are my first ones. They are from March.

These next ones are from March/April. I played around with proportions and styles a bit with these ones.

I apologize for the coffee-splatter and wrinkles caused by them. There was an accident. 

And one with black pen from same session. It's just not croquis if there's no Gollum-pose! 

And a single one from May (without coffee!).

And some from June.