Grammar: Words for objects and people

A word with 'El' or 'Un' before it is usually masculine

Nouns ending in '-o' , '-l' , '-n' , '-r' , '-s' , '-ta' , '-aje' are masculine 

Or anything that is a Male, Day, Month, Language, Seas, Rivers, Oceans and Mountains.

A word with 'La' or 'Una' before it is a feminine word

Nouns ending in '-a' , '-ción' , '-sión' , '-tad' , '-tud' , '-dad' , '-umbre'

A word is feminine if it is Female or a Letter of the alphabet

If a noun ends in an 'E' or an 'Ista' you cannot tell if it masculine or feminine.

examples.

El coche The car

La gente The people

El turista The tourist (male)

La turista The tourist (female)

El dia - Day

El problema - Problem

El mapa - Map

La foto - Photo

La moto - Motorbike

La mano - Hand

If a noun ends in a vowel you can just add an 's' to the end 

eg. una cama --> dos camas

Sometimes you need to add or remove an accent when making something plural so it doesn't change how something is pronounced

eg. Un inglés → dos ingleses or un joven → dos jóvenes

If a noun ends in a consonant except 'z' -> add 'es'

If a noun ends in 'z' -> drop the 'z' and add 'ces'

Days ending in 's' -> Make the article plural but keep the noun the same

Family surname ->  Make the article plural but keep the noun the same