A scrap page
Before I decide how a color behaves in the picture, I want to see it on paper. A scrap sheet lets me test pressure, layer two colors, and find out whether a marker feathers. If the book includes a test page, use that too. Different papers can change the result more than the color printed on a pencil barrel suggests.
A simple sharpener and a soft cloth
A fine point helps with ironwork and narrow stems; a broader side of the lead is useful for gentle shading. I keep a cloth or clean tissue nearby to clear stray dust and protect the page from a hand resting on fresh color. No elaborate kit is required.
A protective sheet
If I am using markers, I place spare paper or another suitable barrier behind the page. A blank reverse helps separate illustrations, but it does not make the sheet bleed-proof. Testing first and protecting the next page make experimentation much more relaxed.
One object worth looking at
A leaf, a piece of patterned fabric, or a ceramic cup can offer a color relationship you would not have imagined from a swatch chart. It need not match the drawing. It is simply a small reminder that color exists in conversation with other colors. The best companion at the table may be your curiosity.