When organizing a room, start organizing from the inside --- drawers, cupboards, containers and closets --- and then organize other parts of the room, such as flat surfaces and the open floor space. This method works for three reasons:
1. Things in the open need a place to go.
2. You need to make room in drawers, containers and cupboards to hold things that were left in the open.
3. You'll handle each item only once. Remember the acronym OHIO -- Only Handle Items Once. There is no sense in putting things away and then having to remove everything to organize that space.
When you finish using something, put it away. Seems simple enough, but is difficult to do. However, this is a big time saver. Clutter attracts more clutter. A pile starts with just one item.
Keep a donation bin hand and use it. When you find something you don't use or don't want, immediately put it in the donation bin. When the bin is full, take it to your local thrift store or another charity.
Keep flat surfaces clear. Flat surfaces can truly become clutter magnets. When one thing is laid down, then another thing comes along and joins it until the entire surface is covered with things that don't belong.
Declutter daily. Organizing doesn't have to be done in huge chunks of time; when it is done a little at a time you can keep organized. Remember --- CLUTTER TALKS -- and it never says anything positive to you!