Determine the scope of the project: Understand the client's requirements, including the type of artwork, complexity, style, size, and any specific deadlines. This information will help estimate the time and effort needed to complete the project.

Estimate time and effort: Break down the project into tasks (sketching, line work, coloring, revisions, etc.) and estimate how long each task will take. Consider personal working pace and experience.

Set an hourly rate: Research industry standards for freelance artists in the same field, taking into account factors like location, experience, and skill level. A higher rate may be justified for more specialized skills or a larger portfolio. Artists may also consider their own living expenses and desired income when setting a rate.

Calculate project cost: Multiply the estimated hours for each task by the hourly rate, and then sum up the costs of all tasks. This will give a rough project cost.

Factor in revisions and contingencies: Add a buffer to the quote for potential revisions and unexpected changes. This could be a percentage of the project cost or a set amount per revision.

Add a profit margin: To ensure a sustainable business, it's essential to add a profit margin to the quote. This could be a fixed percentage of the project cost or a predetermined amount.

Present the quote: Clearly outline the scope of work, deliverables, and the total cost in a professional manner. Provide a breakdown of the costs and terms of payment, along with any other relevant details.