My tools in the ready to go configuration (this photo needs to be updated when I finally get around to making a newer version of my pen holder).

The paint stuff  on the left side go into one front pocket in my current sketching bag and the pen holder (this is not the ultimate version.. but a trial run) goes in the other front pocket.
I nearly always use a cross body bag with two front pockets. (The perfect sketching bag is another topic totally and probably needs another page. Including my walk stool portable stool etc etc)

Using signboard for support while urban sketching

Recently I have starting using a board to support the spine of my landscape sketchbooks and hold my paint tin (inspired my Marc Taro Holmes). Full explanation is here.