Organizing Homeschool Books by Subject or Category

We have accumulated a lot of science, history or other books that pertain to homeschool topics and I wanted them organized even more than just grouped by science or history, etc.  I wanted to split my science up into several fields and here are the ones we did: anatomy, botany, physics, chemistry, farms, earth science, astronomy, zoology and insects. 

I couldn't find any affordable dividers, so I made my own with colorful cards but I do want to eventually make some that are sturdier; something like poster board.  I also did the few language-related books we have, math, government services and geography.  I've yet to do the history shelf but when I do, I want to divide it up into time periods; ancient, medieval, etc.