A free rule: every German noun ending in -ung is die, without exception worth worrying about — die Wohnung, die Zeitung, die Ausbildung, die Bewerbung, die Erfahrung. And the stress falls on the stem, never on the ending.

⚠Gender rules like this are worth collecting: -ung, -heit, -keit and -schaft are all die. That is several hundred nouns you never have to guess at.