Look at your space and see what are you feeling inside about what wants to be done. What would make you feel at the end of the day getting into bed, that you are so glad you worked on. What is calling to you (like a child who wants to be fed, or a plant that needs to be watered)?
It may be beyond what your rational mind may think it needs and wants. The important thing is to just pick something, any small area to work on. Like a garden that you plant, it will begin to create a presence that will slowly inform you and your space.
Pick a small area to do and make it something you can actually complete in the time you've given yourself. Set a timer for 15 min, 30 min, an hour. And just work on it, in whatever way you can with no interruptions. One trick is to work in 15 or 30 minute intervals - they are like focused work bursts - and add on the next burst when you are done until you have found that you have worked longer and with more focus than you might have imagined you could.
Set aside a regular time to do it. Once a week, every two weeks, once a day, every two days. You can also allocate a number of hours per month for organizing and plug it into your to do list when you can. It doesn’t’ matter. The idea here is to do “a little, a lot” (Mark Forster’s Do it Tommorow). Just focus on that small area you are working on and let the rest go for now.
Lightly hold your vision for the area you are working on. Sense the flow, the ease, or the functionality you are looking for. You don't need to get detailed, just have a feeling for what you want. And go for it!