Nouns in Spanish have a gender. Is it hard to tell when a noun is masculin or feminine?

A big difference between Spanish and English is the fact that Spanish nouns have a gender, so, for instance, we would say that a table is feminine and a book is masculin. This is important because if a word is masculin, its descriptive adjectives and articles will also have to be masculin. To be clearer, instead of having a word like "the", we have "el" (masculin article, singular), "los" (masculin article, plural), "la" (feminine article, singular), "las" (feminine article, plural).

It may seem difficult to remember which nouns are feminin and which ones are masculin, but it isn´t that hard, as there are several tricks that can be used to know the gender of the noun. 

In general, nouns ending in "-a" are feminine, and nouns ending in "-o" are masculin. However, there are some added rules and exceptions that can be easily learned. Also, once you start speaking and listening to the language, it´ll just come out naturally.