Most people seem to go through a life phase from around ages 9 to 15 where they learn how to organize and arrange their environment, how to clean up, etc. I am 27 and never went through this phase. Every day I look around my massively cluttered apartment and feel like I'm missing some essential skill that others learned earlier in life. I know this is really basic stuff, but what do I do?
Specifically:
* How do I efficiently clean up an area and keep it clean while still using it?
* How do I put away a large number of miscellaneous items in a manner that I know where they are and can easily be found again?
* How do I put away bowls and food storage containers such that they don't avalanche on me when I open the cabinet?
* How do I organize important documents such that I never lose them and can retrieve them after several years?
* About how much time should I expect to be devoted to house chores each day/week?
* What chores should I do on a regular basis, and how often? (How often should I dust? Vacuum? Clean toilets?)
Pick one small area to start with. We chose the kitchen because it is used several times per day so keeping it clean pays the biggest dividend.
Think about how your storage should be organised. Most frequently used items in the most accessible cupboards. How should people move through the space? Where are the bottlenecks/sharp corners? This is a UX problem.
Throw away all the useless, broken stuff and the stuff that you haven't used in a year. Be ruthless.
Clean your area properly for the first time - every surface, every item. Use powerful cleaning products NOT hippy, earth-friendly coloured water. Wear rubber gloves. Break into a sweat. This first clean is hard work.
Next time you do anything in your area, ensure that it is clean before you start. Throw away rubbish, wipe up dirt, wash up, dry, put away. This should not take long.
Clean up whilst using your area. Clean up after using your area. You are not a teenager, pick up after yourself.
Schedule a time for cleaning. I find Wednesday evenings good because work/TV/social-life is usually empty on Wednesday evenings. It is possible to clean a (tidy) two bedroom apartment top-to-bottom in two hours, but don't expect to be this efficient when you start. Two-three hours once or twice per week is plenty unless you have pets/kids/coalminers living with you.
Take the time to notice that using your area is massively more efficient when it is tidy and give yourself a mental pat on the back. When you mess up (we all do), the motivation to get back to the tidy state should be there. You are now a grown-up.