You pronounce it as if it were not abbreviated. You do not try to pronounce it like an initialism or acronym. The full expression is "et cetera," Latin for "and the rest." The "et" rhymes with "bet," "get," and "wet. "cetera" is exactly like the word "setter" followed by a schwa (indefinite vowel, "uh").

etc. et cetera /ɪtˈset.ər.ə/

It is an abbreviation of a Latin phrase "et cetera", which means "and the rest" in English. It is composed of four syllables, the second of which you put the most stress on.

Thank you! Shukran! :)

etcatera