My current painting is clipped to the easel, along with my palette. I use the handy rubber-tipped clips you can buy in hardware stores. They are perfect to hold a panel but I really wish they were not bright orange.
I use white tape on the floor to mark where my stool sits for the current painting. I sometimes sit and sometimes stand while I paint, but my stool is high enough (and I am short enough) that my head is the same height either way.
This is my prized "dobie" rolling chest of drawers. I have two, and they are perfect for painting in a small studio. (I bought them from IKEA a few years ago and my husband can attest to the fact that they were a PITA to assemble.)
I put my paints on the top drawer, jars of various medium mixtures in the second drawer. My brushes stand in jars that fit perfectly on the shelf on the left side, and the handle acts as a stand for my mahlstick - you can see it leaning there on the right. There must be some better trick for not dropping one's mahlstick, I still manage to drop it a few times a week and wow it makes a loud noise on the wood floor.
Finally, here is a shot of the view above my head: Some fine San Francisco architecture, a bank of afternoon fog rolling in, and a network of wires I confess I've never noticed before I took this photo.