Looking to become an apprentice in Dallas Area (Texas)

What do I need to do to become an apprentice? I've already called over 30 shops in my area, none were accepting or the number was dead. I really want to know what would make me an attractive prospect apprentice. What do I need in my portfolio? I have a gallery online but it is mainly digital art and anthro. Are there certain things I should draw to come across as a good choice? I see swallows, nautical stars, text, tribals, hearts, kanji and portraits the most but I don't know if I should draw things like that for my portfolio. What type of medium should the things in my portfolio be on? Most of my work is digital, on printer paper or on cardstock but I don't know if this is the prime choice to have my portfolio on. What type of medium should my porfolio be in? I do digital, pencils, marker, prismacolor pencils, I have never worked in airbrush and am not very learned in oil or acrylic paint. Are apprentices paid, is it a free exchange or do apprentices pay the artist? I'm not desperate for money i'm desperate for training, I can afford to pay an artist. I went to an Arts Magnet High School for two years, specializing in visual art and am now a freshman at a local community college. I'm majoring in character animation and plan to work in animation if tattooing falls through. Also if you know of ANY artists accepting apprentices in the Dallas/Fort Worth area please give me their number or email, I am very desperate.