I purchased different colored library labels and I've started putting them on my books. Red for history, green for science, blue for early readers, chapter books and novels, etc.
This will allow the girls to help me put the books back on the shelves according to their group. And some of the (lower) shelves need this organization more than the others since the girls are always pulling books off them, but I am hoping that having all the books grouped will make it easier for us to put them back where they go/ find a particular book when we need it.
As I put on the labels, I am also taking a minute to make sure the title of every book is entered into my Goodreads account. Goodreads allows me to keep a free, online database of all the books in my home school library. I can also label these books online according to their type (history, science, etc.) and see all the books with a certain label at the click of a button.
When I am shopping for books at the thrift store, I will often log in to my Goodreads account using my smart phone to check to see whether or not I already have a book. With nearly 1,ooo titles in my home school library now, it's easy to get confused about which books we own verses which ones we've only checked out from the library, etc.
As the years go by, I may have to better organize my collection, but I believe this system, however simple it is, will be a helpful start. Sometimes it takes us as much as five minutes and a lot of stress to find a certain title and that is if we even find it at all! I am hoping to notice a significant decease in the time it takes and in the amount of stress we feel when it's time to go find a certain title.