The really hard part of changing an organization is changing the people, and that's not something I can tell you how to do in a blog post. However, I can tell you about five great practices that will boost your team's productivity, increase quality, and improve communications.
First, use continuous integration. It's a very simple tool with an enormous impact. A CI tool compiles source code after every check in, then runs every available automated test. This means that a developer who checks in code knows as soon as possible whether they've missed a file (oops!), or whether they've broken a test in another area. This type of rapid feedback means that your developers fix their own bugs, and learn from them, instead of having some poor dupe fix all the problems once a week. (See Jenkins for a good CI server.)