I always hear it's a good idea for writers to keep a journal, but what am I supposed to write in it?

Journals are a great place to collect striking details, explore ideas that intrigue you, and practice translating emotion onto the page. Use your journal to develop a keen eye for observation. As you’re out and about in your daily routine, what interests you? What makes you wonder? Gives you pause? It may be the way the sun filters through the trees, leaving webs of shadow on the ground. Or the curious way a grown woman clutches at her companion’s hand, as if fearful, right before she crosses the street. Many writers keep a journal with them at all times. You never know when you’ll come across something that sparks your imagination. With a journal at the ready, you can jot it down before it slips your mind.

The journal is also a good place to freewrite, which means to write continuously—sometimes for a set amount of time—to see where it takes you. When freewriting, just write whatever comes to mind. Don’t worry about how it sounds or if it’s interesting. Don’t stop. Just keep writing. If you can’t think of what to write, then write about that. Keep at it; eventually you’ll gravitate toward something more interesting. Some writers do this on a daily basis as a way to keep the writing “muscle” limber and let ideas rise to the surface that might not otherwise.

You can also respond to writing exercises in your journal. These can be tasks you make up yourself. At a restaurant, for example, you might look at people around you, choose one, and invent his personality and life. On a train, you might jot down the next ten words you see through the window, and draft a poem that includes them all. Personal challenges based on glimpses and chance can spur your creativity in interesting ways. You can also find a slew of writing exercises in books about creative writing. These kinds of exercises can help you write outside your regular groove of thinking, which can take you in unexpected directions. Exercises can also help you develop your craft by encouraging you to experiment with one element, such as imagery or point of view, without the pressure of creating a whole story or poem.

A journal entry may result in an idea for a story, poem, or essay. When that happens, run with it. You might even write whole drafts in your journal. Go back occasionally and reread what you’ve written. Something you dismissed shortly after you wrote it may intrigue you later. Still, some entries won’t lead to much of anything, no matter how many times you return to them. But writing begets writing. And you’re practicing, which makes you all the more ready for those moments that do spark up into flame.

Some writers keep a daily journal. Others use them less frequently. Some writers are picky about the kind of journal. Maybe it has to be spiral bound with lined pages. Or a particular brand that’s leather and pocket sized. But no one says a journal even needs to be bound pages. Ron Carlson once kept a shopping bag full of notes jotted on scrapes of paper. Find what suits you and start writing.