How can I tell the difference between femine and masculine words in german?

Answer 1

Tine is right, but the article die/der can not always be trusted as sole indicator of noun gender (nouns are the words that have their own gender each; adjectives, articles and pronouns get their gender assigned by the noun they stand with or stand for). The form "die" can be nominative and accusative singular of a feminine article, but also nominative and accusative of the plural (there ois no gender distinction in Plural in German, as opposed to French or Spanisch for example). "der" can be nominative singular of the masculine article, but also genitive or dative singular of the feminine article or genitive of the plural.

There are some rules that can help remembering the gender of nouns, but very few of them are both applicable to a sufficiently large number of nouns and reliable (i.e. with a small number of exceptions) enough to make them worth learning.
One such rule was mentioned by Tine: nouns that refer specifically to the male of the species are usually masculine, those specifically referring to the female are feminine. According to linguistic research, this rule applies to 86% of such nouns, but there are exceptions such as diminutives (always neutral, such as Mädchen, Männchen, Weibchen, Frauchen, Herrchen,...).
90% of the German nouns ending in an unstressed "e" (such as "Blume", but not "Schnee" or "Café") are feminine; and all nouns of at least 2 syllables ending in either "-ung" or "-heit/-keit" are feminine, while about two thirds of the nouns ending in "-el", "-en" and "-er" are masculine.

These few rules cover a large part of basic German nouns. It is up to you if you are good at or keen on remembering rules, though. If you are learning German, ultimately it is best to learn the gender along with every new noun. For example, you can colour-code nouns according to their gender on flash cards.

Answer 2

Feminine words have got "Die" in front of them, masculine words have got "Der". There is no rule which you could logically explain it with. Most female persons are female words (die Frau, die Tochter...), there is only one exception, Das Mädchen(neuter) which means girl. Actually, it's not even an exception, it comes from old German "Maid", young lady. And translated like this it means little young lady... And male persons (Der Sohn, der Neffe..) are male words.