I recommend just running "vimtutor" in terminal once you've installed Vim. It's the best introduction. Far better than the online tutorials that sometimes pop up on HN.

Once I got the basics down (15 minutes in vimtutor), I noticed enough productivity gains to use it immediately for note taking and scripting. Then I just decided to jump in and use it for a real project. I learn new hotkeys, plugins, and config tricks every week and I just feel my productivity inch its way up and up.