Expat Advice Needed! HELP! (Rome)

CIAO!
My name is Tim Woolston and I am new to the InterNations website. I will be traveling to Rome in about a month with the hopes of finding a job teaching English. I have a degree in History, with a Credential to teach History and English in public schools in America. I have 3 years of teaching experience in a public high school and a TEFL certificate.
I am wondering if you have any words of advice for me, or answers to any of the following questions:

1. Some websites have said Italians turn a blind eye to working in Italy without a permit (getting paid under the table). Other websites say that you MUST have a “permesso di soggiorno” or work visa to work there. What do you suggest?

2. What advice would you give for interviews? What are Italian business owners looking for? How should I dress and speak?

3. Where would you suggest I look for work first once I arrive in Rome?

Thank you so much if you can help me!
Tim Woolston