I did a Seiko mug design with the help of a professional freelance designer on Fiverr. It is really easy, find the freelancer specializing in the task you have at hand, then you upload the material you have, explain what you are after and also include a rough sketch if needed. Then wait for the result and correct as needed, the better you explain in the beginning the less there is to fix in the end.
Received from postal courier
