If you have a website, comic or any of a hundred other reasons for needing a character illustrator. You will need to know how to find and hire one.
First of all you will need to establish in your own mind exactly what it is you need from the character you need designed. Is it suppose to be aggressive, passive, friendly, scary, big, small, and the list goes on.
You need to establish to yourself exactly what your character’s purpose is, because you will need to be able to clearly transmit this information to the character illustrator. Also you should make sure the character illustrator you find asks for this information, because if they aren’t interested in your requirements, you can be sure they will not do a good job.