Many English-speaking foreigners living here will, at some point, teach English. (If you do, it’s obviously best to get a proper qualification and to work at a reputable school for a while so you get some on-the-job training and benefit from observations and feedback from more experienced teachers. Good schools provide their teachers with ongoing training.)
There are many jobs offered privately through the Living in Bergamo Facebook group and many language schools frequently looking for native English speakers.
If you need a little refresher on (or a taster of) different approaches to language learning and teaching, this free online course offered by FutureLearn in association with the University of Southampton might interest you.
If you want to gain/update/add to your teaching qualifications while living in Italy, the British Council in Milan offers courses, you can check them out here: British Council in Italy (Milan)
And here are some teaching resources that might interest you — please let me know if you’d like me to add anything to this list — I will be adding to it over time, as I remember and use the resources myself.
Teaching children English
Super Simple Learning — not just songs!
Cambridge English for young learners — even if your students don’t need to take an exam, this can help you build a syllabus for your little ones.
BusyTeacher — you can sign up for their newsletter, which lists their latest worksheets, etc
Good old onestopenglish
Business English materials from the Financial Times
Exam info (IELTS, TOEFL, TOEIC, Cambridge)