Der= Masculine Die= Feminine and Das= Neuter Instead of remembering a word like "Junge" or "Mädchen", get used to memorizing "Der Junge", and "Das Mädchen" while you're still learning the basics. I'm still a beginner but I'm having to re-learn all the nouns because I didn't take the time to remember that.
Basically no -- grammatical gender is essentially arbitrary.
(And not even consistent between languages that have grammatical gender. For example, German considers "sun" feminine but "moon" masculine, while French speakers would assign those nouns exactly the opposite genders.)
In general: you can't. You just have to look it up and memorise it.
(For example, what gender is Leiter? Answer: it can be either masculine or feminine, depending on the meaning -- die Leiter is "the ladder", der Leiter is "the leader". So you can't generally tell from the shape of the word what gender it will be.)