Wallpaper your closet to make it an attractive place to work.
Hang three shelves for books and supplies. Staggering them on the wall creates more visual interest. Paint them in your favorite color. You can purchase a board at any major home and garden center. They will cut it for you.
Make a desk out of two-drawer filing cabinets. You'll need two of them and you can usually find these at thrift stores. Place wheel stands on the bottom of the filing cabinets to make it easier to move the desk. Arrange the filing cabinets on the right and left side of the closet wall, and place the plywood on top for a workspace. The weight of plywood will keep the top securely in place. Paint the cabinets and plywood in your favorite color before installing them.
If there are one or two doors that open out from your closet, paint the inside of the doors and frame pegboard on these for hanging supplies. Paint the pegboard the same color as the door.
Hang an attractive light fixture from the ceiling of the closet. If there isn't wiring for electricity in your close, hire someone to do the work.