Hello I am a native Dutch speaker and there is no trick to know if you say de or het. Some people may tell you some rules but they do not apply with every word . My advice is to learn them and if you really don't know to say them in your head with the word to look witch one sounds best this trick works almost every time.
Sort of. It is still gender related - the linked thread above is a good explanation of this, and the ratio of De/Het is about the same as En/Ett. This means you could reasonably assume a noun is De if you don't know, but you still need to learn the rules behind it. In fact, Swedish doesn't have many concrete rules behind En/Ett, so Dutch may actually be easier to learn.