Only a bookshelf can truly hold a reader's history and future at the same time, while the present is usually found in a book bag or on a nightstand nearby. A lifelong reader myself, I've always had an obsession with seeing a person's bookshelf, to get a sense of what they've brought inside their home and their head. Bookshelves are universal in that almost everyone has one, and unique in that no two collections are the same. They reflect much more than just the book-buying habits of their owner. Titles are easy to acquire and even easier to sell off or leave behind, so if it's worthy of your shelf space, I want to know why.

Photograph: Lori McCaskill

Sharing your shelf is sharing yourself – showcasing the building blocks that have crafted your knowledge, personality, and identity. While the internet has long valued the voyeurism in sharing and viewing photos of beautiful books as objects, grand libraries as cathedrals of intellect, and bookshelves as marvels of design, I created ShareYourShelf.tumblr.com as a way to attach individuality and ownership to these previously anonymous assortments of titles. I also don't have enough time to visit everyone's living room, but that doesn't leave me any less curious as to the books there.

Photograph: Jeff Kaplon

Your bookshelf is an intimate physical representation of your accomplishments (titles as trophies earned), aspirations (that ever growing to-read pile), associations (that book your boss gave to each employee), personal development (those self-help titles that urged you to talk to strangers), guilty pleasures (50 shades of beach reads), escapes (sci-fi to some, travelogues to others), memories (meeting that author, visiting that indie shop on vacation), interests (the bigger the Star Wars fan, the more Star Wars books) and countless other tells that another reader would unconsciously and immediately compare against their own shelf. And that's just the ingredients – how you organise, arrange, and display these titles should impart even more insight as to a reader's personality.

A bookshelf's organisation, or lack thereof, can show that practicality and discoverability is the priority when shelved alphabetically by author (as is the traditional way). But if it's arranged by colour or trim size of the book spines, the owner obviously prizes appearance and display above finding the right title quickly. More likely the shelf is representative of how the reader sees their own collection: frequent favourites at eye level, grouped together according to genre/topic/theme and other commonalities. I imagine each section, as its own book club where a title relates to the ones around it, clustering authors that would have a lot to discuss among themselves. Speaking of which, here are my shelf-organising tips …

• Pick a system and stick to it. A nitpicker will always find something they think you missed; so if you're ordering alphabetically, don't tire out before you get through the Zs. If you have a lot of a particular author/interest, try to keep them together so it's clear what you're really into reading. It's not a given that someone with a lot of Hemingway on their shelf likes him more than you do, but it's more likely.

• A well-rounded person boasts a diverse bookshelf. Variety is the mark of an interesting reader, so make sure to include the classics among the contemporary, the highbrow with the mass market, the fiction alongside the non-fiction. It'll go a long way to ensure you'll have something to discuss with almost anyone.

• Have a growth strategy. You're never really done buying books. Even if you love your e-reader, you're going to find something you have to add to the cluster. Identify some less relevant titles that can be relocated and keep them at the edges of your shelves to make it easier to adjust.

• Finally, if you are going to photograph it, make sure you hold the camera steady – we all care most about being able to identity the titles. Most submissions either take the close-up detail approach to guarantee this or give up and go big-picture of the whole bookshelf and room to see it in context. The best can manage both. Someone will see your shelf, zero in on a title that stands out or means something to them, and ask you about it. Maybe you'll even still be talking when the wine runs out – nothing starts a conversation better (online or off), than a bookshelf.