Most speakers of modern Hebrew seem not to pronounce the ayins. Only Jews
from Arabic speaking countries such as Yemin actually pronounce the 'Ayin
when speaking Hebrew. If you can find a native speaker of Arabic, he/she
would be able to teach you to pronounce the 'Ayin since Arabic still uses
the 'ayin. Basically it is a vowel sound with a constriction of the
throat (a bit like talking while being strangled). Better heard than
described.