Lessons learned in the classroom: After you purge out items you don't want anymore, either physically lay everything out in the center of the room or make an inventory list of everything.
Divide your room into zones or stations and assign each item to a zone. At each station organize materials into piles by task, then by frequency of use. Think through tasks and make note of any gaps in tools, supplies, or shelving. Try to avoid having to get up and go to another station to retrieve a tool or supply when you are in the middle of something.
Next,decide what organizing containers you need by size and type. You may need containers within containers to keep tiny things organized. When I was teaching, my containers were often recycled ones like oatmeal, ice cream or laundry soap boxes. Label each container and its location clearly.
I don't have a dedicated sewing room. I have corners throughout the house. I need to reorganize soon because its been awhile since I did this.