Things that have worked for me in the past and present:<p>1) Just use them. When you're demoing the product after a certain amount of work, explain how this new tool you've incorporated has benefitted the project in some major way.<p>I got Django accepted into the federal government doing this in what I believe was its first deployment (agencies don't generally talk, so there's no way to confirm that.)<p>Python was an accepted language, so I just wrote code in Django, explained how its use 'as a library' would expedite future releases, enable RAPIDER development and keep a clean, structured codebase, which was something they were having troubles with.<p>2) Choose products that actually DO provide benefit to the project. Sometimes it's hard, as a developer, to know the difference between "I want to use the Play Framework for this" and "The Play Framework is the right tool for this job." I often struggle with this myself, as I want to learn new things, and it's easy to get caught up in a new toy's feature list, and directly apply that to pain points you're having currently. When I was learning Ruby, I saw it as the tool to fix a lot of problems. Then, when I was learning Python, I saw the flaws in Ruby, and laughed at how I ever thought Ruby was the right idea. This isn't meant to be a slight on Ruby, as I'm guessing if I'd learned them in reverse order, I'd have had the reverse opinion.<p>It wasn't until well later that I got a good baseline for what each was actually better at (aside from the marketing points), and how to determine which one might fit a project better. It was even longer that I could make an emotionless decision to determine which actually made more sense _for a given project_.<p>If you have a real, valid reason to select a new language/framework/tool, and can both express the pain point to your boss, and illustrate how this new solution can reliably resolve that pain point without introducing equally sized, but different pain points, then it should be an easy sell. If you can't illustrate that, you might be a victim of your own personal bias. Don't feel bad, it happens.