There's no one silver bullet that you can show your co-workers that agile methodologies are the way to go. The best advice I can give you is to take small steps. If you want to introduce TDD, show an example of what a class looks like when it is developed with a test first vs when it is developed code then test. Hopefully the development time will be faster and then when you are complete, you have the test written too.
Does your organization currently write unit tests? I know this might be a silly question, but so many organizations don't. If not, you're going to have to first show how unit tests are beneficial.
Also by working in small iterations you can show a better roadmap for your product and hold people more accountable, etc.
Hope this helps - but the key is that small steps. Don't just tell people that agile is good.
I've found the best way to convince someone is to help them see what's in it for them. I suppose your manager maybe focused on business values such as time to market, product cost, quality to customer and others. First learn what his or her priorities are, and then choose the practices that will help their priorities directly. Consider doing so incrementally with measurable success criteria.
It is this kind of question that is directly answered in the book. To get a further idea of how this might be done for technical practices, such as TDD, ask yourself "what business value does TDD deliver?" Then find out if your manager is interested in such values - with TDD you'll improve quality and flexibility, but you'll probably (at least initially as your team learns it) reduce time to market.
Amr Elssamadisy<br /><a href="http://www.amazon.com/Agile-Adoption-Patterns-Roadmap-Organizational/dp/0321514521/ref=pd_bbs_sr_1?ie=UTF8&s=books&qid=1220909336&sr=8-1" target="_blank" rel="nofollow">Agile Adoption Patterns</a>