Think about the life you actually live in, not the imaginary one of the future or past.
Do you need it, love it and use it? Then keep it. If you don't agree with all three criteria, get rid of it.
Store like with like in the room you use it.
Avoid perfectionism and all or nothing thinking. Organizing can be daunting. Take it a step at a time. Start with a drawer or cabinet. Don't start too large and get discouraged.
Purge once a year at least.
Don't put anything away dirty or in need or repair.
Keep a tote bag on the door handle of the door you use to leave the house. Place things you need to take with you for your errands in it as you come across them. No last minute hunting for things before you leave the house.
Get a good shredder and use it constantly. It is much easier to shred a few pieces of paper at a time than stacks. A lesson I learned the hard way.
The floor is NOT a storage option.
Stick to routines: Do the same things, the same way every time: keys, wallet, schedules, shoes backpacks all go in the same place every time.
Set a timer for 15 minutes, do what you can and then stop. You will be amazed at what you accomplish.
Along the same lines, during commercial breaks take care of simple chores. Load or unload the dishwasher, you can vaccuum a room or two during a commercial. You can change out your laundry from the washer to the dryer. Make it a game to see how much you can get done in those few minutes.
Put your phone and tablet/ipad away while you are trying to organize. Multitasking is the enemy of organization.