My father explained it to me like this:
Het Meisje = the little girl
De Meid = the girl
De Jongen = the boy
Het Jonchie/Jongentje = the little boy
Notice the vowel on the end of the nouns? My father says that generally this is when you would use "het" over "de"...but there are exceptions as explained in other comments of this discussion. My dad said that he just knows them because he grew up speaking the language and that if I wanted to learn, I would just have to memorize the exceptions.
Hello! My mum explained it to me like "Het" is the feminine article and "De" is the masculine. It is not exactly like that, but since we speak spanish and in spanish it happens the same thing, I understand it like this. To learn it, I just picture the thing with a gender. For example "Het paars", I picture a pink unicorn, and for "De auto" I picture a big black Range Rover >< It works for me! For "De vrouw" for example I just picture a woman with a moustache...
It reminds me of how German has diminutive endings ("-chen" and "-lein") and words with these endings are neuter. The German word for "girl" is "Maedchen", a neuter word. Beginners in German have trouble accepting that. As I've been learning German for quite a while now this quirk is so familiar to me that I don't have a problem with "het meisje" being neuter.
look it up on google translate and press the figure next to the microphone. (see link) https://www.google.be/search?dcr=0&source=hp&ei=JKr3XMuHMcbMwAKS2Y_QBQ&q=engels+nederlands&oq=e&gs_l=psy-ab.1.0.35i39l2j0i131l6j0l2.4376.6683..9120...2.0..0.60.193.4......0....1..gws-wiz.....6..0i67j0i131i67.JKjMLhXTSE4