Tailwind Tribes are a great way to boost your Pins' visibility for very little effort.
I used to recommend that my students try to join group boards, but most of the groups are only open to bloggers now, so I now suggest Tailwind Tribes as an alternative!
Here is a good list of Tailwind Tribes, I'll try to keep adding to this as I find more!
Blogging & Business
DIY & Crafts