One great idea I've seen about doing a sweeping de-clutter is, if you can't bear to throw things away or give them away, put them in boxes, tape the boxes up and put them in storage somewhere, labeled with the date you did it (basement, garage, even an unused corner of a spare room would do).
If, after 6 months or a year (whatever your comfort level is) you haven't opened the boxes to retrieve the contents, you probably didn't need the stuff in the first place.
It's drastic, but sometimes you need to start drastic to get things under control, then it will be easier to catch up and keep up later.
Also, I'll second the suggestion to have a friend help you with this step. They can talk you out of holding onto 3 different turkey basters just in case you need them all later.
Other than that - since you do know that you need to change, maybe post specific areas that you know are difficult for you and people can help with more pointers. Is it cooking, or deep cleaning, or general daily maintenance of clutter, or . . . There's so much, it would take several books to detail it all, but one thing at a time we can definitely help with.