ą, ę are pronounced like French on, in (in: bonbon). The vowel ą is pronounced like nasal o, the vowel ę – like nasal e. It is like this but only before f, w, s, z, ś, ź, ż, rz, ch.
The pronunciation:
om, em before b, p: stąpa, tępy
on, en before t, d, c: kąt, tędy
oń, eń before ć, dź: zaginąć, pamięć
ong, eng before k, g: mąka, ręka
o, e before l, ł: minął, minęła
Finally, “ą” is pronounced as a nasal o, but “ę” is completely denasalized and pronounced as “e”: miną, minę.