Here is a mini-project for you: the black hole (aka under your kitchen sink). My first suggestion is to consider the location of your trash/recycling receptacles. Are they conveniently located or do you have to leave the room to recycle a can? If you clear enough space under your sink you might want to consider keeping small trash cans for recycling there (see photo). Next, pull everything out and begin to sort and purge. Get rid of products you don't or have never used. Group remaining products into categories (e.g., carpet cleaners, dish soaps, window sprays, etc) and purge duplicates. Next, put what is left back under the sink or move it to other locations in the house as appropriate. Put products you use most often in the front and those less frequently used in the back. Good luck!
There is a point in some organizing project when you should stop and say "this is organized enough." If you over-complicate a system it often makes it too hard to maintain. Another side effect is that you may dread your next organizing project because you remember how much time and energy your last project took (aka: perfection causing procrastination).
The holidays are over and it's time to look forward to the new year. How can you turn dread into ease and enjoyment next December when it is time to pull out your holiday decorations? Before you just shove all your decorations in a box (tangled/non-working lights, broken ornaments, and all), organize and pack them like a pro now. It doesn't take that much more effort and you will thank yourself later, I promise.