I am a burned out graphic artist, with (I feel) transferrable skills from my years of experience and extensive volunteer expereince...does that make me a career changer? Am I in the right place?

What is the best way to cold call companies that aren't necessarily advertising positions and  when you do not have a contact related to that company?

Is an introductory cover letter and follow up call best?

Cover letter, resume,  and follow up call?

Cover letter, abbreviated/skills resume, and follow up call?

I am currently employed and enthusiastic to get started on something new. Thanks in advance for any help you can give me.