First and most important thing is the chair. It needs to suport your spine and make you feel very comfortable. Plastic, wooden, metal chairs can be good for short-sit. The office chair needs to suport you for many, many hours of work.
Second thing is to have as many drawers, boxes or baskets as possible – to keep all the papers in great order. It is not „The perfect housewife” competition, it’s just a favour you give to yourself. Looking for some important dokument in a big rush can be very stressful. Don’t let it happen, ever.