Because there are no templates, you can also use this notebook for non-list things, too. You can journal or doodle or hand-letter a quote. You can tape in photos or ticket stubs or receipts.

Your bullet journal is a catch-all for everything that itches your brain. It’s your to-do list and your calendar and your junk drawer.

Why do people bullet journal?
There are a lot of reasons, but I will name just a few:

Writing things down can make you feel better, mentally and physically
Decades of studies have demonstrated a positive correlation between writing (particularly journaling) and health. Take, for example, the many studies of psychologist James Pennebaker at the University of Texas. In one, he asked half of his participants to write 20 minutes a day, three days in a row. That's it. Even months later, those who journaled were much happier than those in the control group. As New York Mag once reported, "in the months after the writing sessions, they had lower blood pressure, improved immune function, and fewer visits to the doctor. They also reported better relationships, improved memory, and more success at work."

Research has also suggested that writing things down improves immune cell activity and reduces antibody counts for people with viruses like Epstein-Barr and AIDS. Journaling could also improve memory and help you sleep, according to some studies.

The power of free-association:
Beyond the benefits just mentioned, therapists often use journaling to get their patients to better understand how parts of their lives relate to each other. This helps people triangulate who they are and how they might react to different actions and emotions. Bullet journals, which by nature are collections of tasks and ideas that span the full spectrum of a person's physical, mental, and emotional life, are particularly well-suited for synthesizing information and drawing conclusions from it.

Delicious freedom:
If you like Harry Potter, you can think of a bullet journal kind of like a Pensieve—a place to unload thoughts and reminders, which frees and focuses your mental and emotional efforts. Once you’ve written down all the tiny things you need to get done, you give your brain the capacity and the encouragement to actually do the things.

The manual effort:
It’s easy, particularly (old man voice) these days, to underestimate the swell of satisfaction from making progress on something physical. To-do lists give nerds like me the thrill of checking something off. It’s a genuinely pleasurable experience.

Bullet journaling takes that a step further: By treating task lists like archival records of your life, as precious as letters from a loved one or photos from a vacation, you’re letting yourself feel proud of small accomplishments, and soothing your weary existential soul by recording the things you’ve done with your life—at every scale.

It’s just fun as hell:
Here are some of the things people commonly use when bullet journaling: gel pens, stickers, decorative tape, highlighters, and magazine clippings. Here are some of the things people track: book and movie recommendations, vacation plans and packing lists, moments of gratitude, favorite Prince lyrics, and sex stuff.

How do I start a bullet journal?
The fundamental anatomy of a bullet journal is so blissfully simple you may weep:

Step One: Index

Here you list where to find spreads that you may want to refer back to in the future. (A one-off grocery list? Probably not. German adjective declinations? Add it.)

Some notebooks already have numbered pages and room for an index, but more on that later.

Step Two: Future log

You can refer to this any time you want to make note of a date in the far future. If it’s January, you probably haven’t created a June spread, but you want to note your college roommate’s wedding anyway. That kind of thing.

Step Three: Spreads for planning
These generally fall under three categories: monthlies, weeklies, and dailies.

Bullet journal monthly spread
Your monthly spread (above) is where you write down appointments, pay days, meet-ups, classes, vacations, holidays, due dates, etc. There are a few ways to do this. Personally, I just draw up a calendar on a two-page spread, leaving room for a box that says “next month” to jot down future items, and a tinier version of the following month’s calendar, like this.

Another popular way to get a glance at your month is to use a “calendex,” where one writes down page numbers as opposed to event titles. For example: If you took notes on a meeting you had on the 13th, you could go to the calendex for that month and make a note of the page number by that date. Here’s what it looks like:

Others (including the creator of the concept) use a vertical version, so the month looks more like a list.

To be totally honest: weekly planning (above) doesn’t work for me. The scale is too weird. I either want to dump every tiny task in or nothing at all. My impression is that people who don’t have a lot of tasks to do every day (maybe their jobs are much more straight-forward than mine), use a weekly spread as opposed to the long, convoluted day-by-day pages I prefer.

I do, however, use these stickers from Muji to write down my non-work appointments for the week: German class, drinks with friends, medical appointments, and more.

Daily spreads (above) are the bread and butter of your bullet journal; at its core, a simple to-do list, bracketed (if you want) by journaling, doodles, and tip-ins. (Tip-in, noun, planning lingo meaning ephemera taped in on one side, so it’s like a little flap on the page.)

Step Four: Collections
Collections are lists or charts that fall outside of your planning spreads.

You can have collections that track spending, the status of job applications, your sleeping habits—basically any "collection" of thoughts you'd like to keep on hand. Collections like these are scattered throughout my journal, and have no explicit tie to the daily spreads that surround them. Other collections relate to your dated spreads, like grocery lists, money spending trackers, and monthly gratitude logs.

What are the best supplies?
Again, you can bullet journal in any notebook, using any writing implement. If you insist that you need a whole new set-up, though, there are a few unambiguous fan favorites to consider:

The Notebook: Leuchtturm 1917

If you’re buying a shiny new notebook anyway, don’t mess around with anything but a dot-grid. It keeps your handwriting from drooping, but feels as liberating as a blank page.

The Leuchtturm 1917 is popular because the book already has an index and numbered pages. It’s also a lie-flat hard-cover, which journal nerds know is just the best. The grammage of the paper (80 grams per square meter) is also superior, so if you’re one of those people who can’t stand bleed-through or ghosting—or you use fountain pens or some other particularly inky implement—this is a good buy.

UPDATE Aug. 25, 2017: Leuchtturm 1917 is dead. Long live Scribbles That Matter. It comes in a dot grid. It comes with page numbers. Its paper is even thicker, at 100 g/sqm, which means less bleed-through. You can find it here.

That being said, a Leuchtturm will cost you $20. Personally, I use a $7 dot-grid notebook from Muji. It’s cheaper, I don’t mind numbering the pages myself, and I think everything that comes from that store is imbued in an aspirational, ethereal quality that I should not even try to explain. It’s like Marie Kondo herself has held each product and encouraged it to give me serenity and pleasure. But that’s just me!

There are also many Moleskine die-hards, but the price is steep, the pages aren’t numbered, and the paper is a bit flimsier (70 g/sqm) than that of the Leuchtturm.

The Pens: Pigma Micron, Pilot Juice, and Staedtler Tri-Plus Fineliners
I started my bullet journal with a set of 12 gel pens from Muji I got for $12. I love these pens, but must admit to true aficionados that the ink does occasionally skip, and they smear when used in conjunction with a highlighter.

The very best gel pens, I believe, are the Pilot Juice pens in size 0.38mm. They’re super thin, come in fun colors, and don’t smear—even for lefties and people who are super into highlighting.

The Staedtler Tri-Plus Fineliners are top-notch color pens, too. They don’t bleed through and don’t smear. The difference is that they have metal-encased fiber tips, which (to put it in pen nerd terms) simply aren’t as expressive as bolder, inkier fountain pens or, in my mind, gel pens.

For a high-quality basic black, go for Pigma Micron. They come in a variety of tip sizes (I like 03 size, which is 0.35mm), plus the ink is of archival quality and virtually smudge-proof.

The Pencils:
Get out of here.

The Highlighters: Mildliners
Mildliner highlighters are a favorite of teens with incredible taste and incredible Tumblr followings. They come in soft colors like lavender and gray, so they highlight without being jarring on the page.

Other stuff:
Get a ruler. I like this one or this one, which is also a protractor of sorts. I’d also recommend getting a clipboard, if you don’t already have one, because it means you can journal from the couch. You can also get stencils, stickers, and washi tape, but I have very few opinions there. Follow your bliss.

TL;DR Writing stuff down is cool again—and just might be the key to getting shit done.