Write To Do lists in the evening.
This will help you to know exactly what you have to do throughout the day right away. Of course you can add things the next day but writing it the evening before makes sure you can organized start your day.

Have a notebook with a pen next to your bed.
If you already lay in bed, prepared to sleep and right then there’s some kind of thought coming up in your head. The notebook will make sure that you can easily write it down so you can sleep without any worries that you might forget it while sleeping. Also it will free your mind.

Find the fitting calendar for you.
There are several different models you can choose from and of course there are many apps as well. You got to find out what works for you because a calendar is the most useful thing for planning and organizing but of course only if you actually use it. Otherwise it won’t help at all. You can also use different calendars for different purposes.

Have a clean and organized room.
Make sure that you are able to find all your things right away. It makes sense to place things that belong more or less together in the same area of your room and to put it where it belongs (in your opinion). Not only is it easier to keep your room clean if everything has a fixed place but also it will be more motivating to work in an organized area.

Do any tasks as soon as possible.
May it be homework, packing your bag or whatever you got to do, do it right away. I find it motivating when my tasks are done as fast as possible, but what is sure for everyone is that this method makes sure you don’t end up with a huge amount of work to do and don’t even have an overview on it anymore.

Have a weekly plan.
I’m pretty sure that there are some tasks you have to do every week like e.g. cleaning.
You can create a personal week plan were you write down which of these kind of tasks you want to do on which day. You prepare this plan one time and then follow it every week. Probably after some weeks you developed a routine and don’t need it anymore, but you can keep it somewhere just to be on the safe organized side.