My studio's chair was kinda old and the seat was flat, so I repaired it and turned it into a tres chic element in my studio. I started taking the pics after dismantling the chair, sorry for the missing pic of the chair before the makeover.
Step 1: Find Your Victim
Sorry, I started dismantling the chair before taking the picture.
Step 2: Dismantle the Chair and Clean.
If you want to paint the plastic parts as I did you must deeply clean all the parts, so the paint sticks well to the plastic.
*Ask your cat for help, mine helped supervising all the process
Step 3: Add Primer
Add primer to the plastic to ensure that the paint stays where you want.
Step 4: Paint
Paint and let dry. It's about 18 hours so the smell of the spray goes completely away.
Step 5: Now the Cushion
-Remove the staples. I did it just with one side for making it easier.
-Take some stuffing material, I got mine from a crafts&fabric store. (and it's kitty aproved)
-Cut the stuff by the size of the chair
-Fill the cushions and re-staple.
-Get your new fabric and cover the cushion with it. Staple. (sorry, no pic)
Step 6: Assemble
-Get all your parts and put them together again.