I have started to slavishly adhere to the principles of Test-Driven Development (TDD). Now I write about twice as much code the first time around, but it always passes QA the first time. It actually speeds up QA, because that team can analyze my End-to-End tests, which I write first, finding defects in the specifications before they start their testing.

Overall, I would guess this triples to quintuples our speed of development.