Be consistent, stay flexible
Consistency is key to great photography: we want to have similar aesthetics and subject matter across a collection of images - be it a book, a zine or any other kind of project.
I believe that new ideas are very important as well, though. Staying flexible, experimenting with new mediums, shapes or textures, creating something new and different to push your creativity beyond its previous limits.
The balance between consistency and flexibility is a delicate one: we don't want to be all over the place and try to do everything, but we don't want to get stuck at doing things the same way over and over either.
As you know, I like the square format. I find square images very pleasing to the eye and it also brings consistency when I put them together (there's no landscape vs portrait debate).
Lately, I've been experimenting with panoramas: very long images. I don't always take them with that idea in mind, I "see" during the editing instead. I don't even use special equipment or software to create them, they are just crops.
I've also been shooting with my phone using an app called Slow Shutter Cam, which lets me take longer exposures than the stock camera app. I like the effect it creates when used walking or even from a moving vehicle.
These are just two of the things I'm doing to switch things up and keep my mind fresh and away from doing the same thing over and over.
Remember to be consistent and to stay flexible, find the balance that works for you.