One thing that helps me a lot is to tackle the project one item type at a time. For instance, I dragged every single pair of footwear I own out of the closet and spread them all out where I could see everything I had all at once, and then go from there. It helped me see that even though I had, say, five pairs of tall boots, only one of them is practical for bad weather, and all but one pair are more than four years old. And one pair I simply don't enjoy wearing.
I do the same for skirts, dresses, tops, sweaters, tees, jeans, pants... and don't just go through them IN the closet -- pull them all out and spread them out over your bed or wherever you have good light and space to see and assess everything. This helps you to evaluate color, condition, etc. For me, this process breaks the task into smaller, more manageable pieces and helps you see where you may have excess and where you have gaps.
Good luck! Post pics and let us know how it goes. I love editing.
