"I read the newspaper"
Translation:Ik lees de krant
Het: diminutives, places, metals, substance names, games and sports, languages. De: fruits trees and plants, rivers and mauntains, numbers and letters, most words for persons (de ober=the waiter) and all plurals.
I believe this are the basic rules, there are a lot more and some exceptions, but for now this might help. (not all dutch have it right all the time either, you'll be fine).