The Bullet Journal Method: This is the book that describes the method. I read it in 3 days and loved it.
Dotted Grid Notebook: These notebooks come in different sizes, but a couple of my daughters have been using the bullet journal method for a while and recommended this size for taking along in a purse easier.
I have found this to be true. To use the system well, it is very helpful to have your journal with you as much as possible.
I actually accidentally bought a lined journal first time around. It works, but is not as flexible as the dot grids.
Staedtler Color Pen Set, Set of 36 Assorted Colors: These fine point pens don’t bleed through the pages of my journal. I’m not particularly artistic, but I find that colors help me organize, as well as make it easier to read my lists and charts.