One of my projects this summer was to redo my binders. My students are required to have a 3 ring binder that they carry with them back and forth from home to school EVERY SINGLE DAY! It becomes such a habit, and they feel lost without it! The parents know to look for it and it has become a survival tool for all of us. My team and I try to keep it pretty simple for everyone involved, so it has 5 key ingredients!
2.) A clear plastic pocket (page protector) is the first item on the inside. I label it with MONEY & NOTES! It's transparent AND has a pocket on the bottom so nothing falls out! The parents and I can SEE if anything crucial is coming home or to school. Kids put their field trip money in there, transportation notes, etc. I put positive (mostly positive) notes about their child in there!
3.) Our school orders student planners for each and every student. It contains a yearly calendar and other special things in there unique to each grade level. The kids really like these! We use them to do a Daily Agenda in. It's my students' first job of the day to come in and copy their agenda from the board into these planners DAILY. That way when they go home, their parents can see exactly what topics were covered that day. Parents initial them nightly. I cannot remember who our school orders them from, but they're available everywhere. Amazon even has them!
4.) Two folders with pockets are the next items in the binder. One of them is labeled "Take Home." The stuff that goes in here goes home and DOESN'T come back! It's mostly graded work, mail from the office, etc. It's emptied nightly. The second folder is labeled with SOCIAL STUDIES & SCIENCE. Our 3rd grade actually changes classes for Science and Social Studies. I teach my kids Social Studies for 4 weeks straight, then they switch to my teammate for Science for 4 weeks, while I teach her kids Social Studies. Therefore they're either in S.S. OR Science...never both. So that folder is used for those subjects. We create and work on a lot of things in 4 weeks that we don't want to send home permanently. The students have a unit test at the end of those 4 weeks, so a lot of the material they need to study with is IN this folder. Parents (and students) are "trained" that everything in this folder STAYS PUT until after the test! 
That's it! In closing, I have good news and bad news! Bad news always goes first, right? I have a bunch of binder covers...REALLY cute ones! (monkey, owl, rock star, giraffe, sports, frog, ocean, puzzle, etc.) available in my Back to School Packs on TpT! They're not free though, because the packs are many, many pages long full of activities for the first few days of school! The binder covers are included in that pack! HOWEVER, that being said, you know I DO LOVE ya' and I can't really stand NOT giving you something to work with. :-) So I do have a binder cover in 4 different colors that's generic enough that you could use with any grade level and any theme....and it IS FREE! So grab your favorite color and go! Click on image to take you there!
Bananas for organization tools that work,
