Take everything out of your backpack first, including any smaller compartments. Next, tip it over a trashcan and shake it to get those last few scraps, crumbs, and bits of lint out.   If you’re starting with a brand-new and empty backpack, you’re way ahead of the game. If your backpack is stuffed full of papers, books, and other stuff from your previous semester, empty it completely. In your first pile, place all of your school textbooks, folders, binders, and notebooks. In your second pile, place your school supplies, such as pens, pencils, erasers, glue, etc. In your last pile, put the other items that you use on a daily or seasonal basis, such as your lunch box, scarf, mittens, etc.   If you take your laptop to school, you should put it in the first pile too. Discard or put away anything that doesn’t fit in any of these 3 piles, such as trash, candy, toys, extra phone chargers, etc. Backpacks typically have 1 large compartment and at least 1 small compartment. Open up the small compartment, and start putting your school supplies away into it.   Some backpacks even have slots for pens, pencils, and cellphones. Use these for those items. If your backpack doesn’t have a smaller compartment, get a pencil bag. Put your supplies into the bag, then put it into your backpack. For example, put all of your English books, notebooks, and binders into 1 pile, and all of your Science stuff into another pile. If you have any loose papers, put them away into the right folder or binder first.   If you need to buy new binders, folders, and notebooks, consider color-coding them. Use a different color for different subjects, like red for English and blue for Science. Stack binders with their spines facing away from each other. This will create a straight stack rather than a sloped one. It will take up less space. Unless you want to lag around a heavy backpack that is almost as big as you are, there is no need to pack everything. Each morning or evening before school, go through your backpack and take out anything that you don't need for the next day. Put everything that you do need back into your backpack.  Leave the stuff that you don't need at home or in your locker. This also goes for school supplies. If you take art class once per week, there is no need to carry around your art supplies every day. While not absolutely necessary, this can come in handy, especially if you are in middle school or junior high. If you get a permission slip or report card that your parents need to sign, you’ll need a safe place to put it. Use a separate folder for this purpose.  Place this folder behind or in front of the other books and folders. Things like lotion, hand sanitizer, and lip balm may come in handy every day, so you can leave those in your backpack for the entire school year. Other items, such as scarves, mittens, umbrellas, and sunglasses, will only come in handy during certain seasons. You should leave these items out until the weather calls for it.   Instead of using full-sized lotion and hand sanitizer bottles, go for the mini travel-sized ones. You'll need to replace them more often, but you'll also save space. If you live in an unpredictable climate, then having a warm hat or an umbrella might be a good idea.
Empty your backpack. Sort everything you’ve taken out into 3 piles. Put your school supplies into the compartments in your backpack. Sort your school textbooks, notebooks, folders, and binders by subject. Pack only the notebooks, folders, and books you need. Add an extra folder for parent-teacher communications. Change out your extra items with the season.