Before you decide on any of the above mentions Wonderful suggestions, I would just get a cup of coffee, sit in the room (hopefully you can start with a totally empty room?) and move the chair around the room to decide where you want to sit and sew.
PICTURES - Before, During, After, and then the redo. You will most likely change a few things after you get it set up.
I agree with LOTS of storage for fabric and notions. You may have empty storage space to start with , but it will fill up quickly.
LABELS - if you have stuff in bins, or drawers, or closed containers labels will help you find things easier.
Have fun and keep us posted!