a) Descriptive adjectives that describe the qualities of a noun (what something or someone is like; such adjectives of color, size, etc.) generally follow the noun they modify

Clase aburrida --- Casa grande 
 
Libro rojo ---  Carpeta naranja 
 
Hombre pobre --- Paisajes tropicales 

b) Quantitative or limiting adjectives, numerals, and demonstrative, possesive adjectives precede the nouns they modify

Mucha tarea ---  Cinco peras 
 
Otro alumno ---  Cien pesos 
 
Pocas oportunidades ---  Esta persona 

c) The adjective comes first at the start of a letter

Estimado Sr. Carlos Dellini ---  Queridos amigos 

d) Adjectives denoting nationality follow the noun:

Estudiante ecuatoriano ---  Libro norteamericano 
 
Alumna peruana --- Escuela mexicana 

e) The adjectives malo, bueno, primero, tercero, alguno and ninguno precede the nouns they modify.

Malo is shortened to mal and bueno is shortened to buen when placed before a masculine singular noun. Primero is shortened to primer, tercero to tercer,alguno to algún, and ninguno to ningún when placed before a masculine singular noun.

Un mal auto --- Tercer libro --- Ningún cuaderno 
 
Un buen libro --- Primer semestre Algún mesero 
 

f) When it follows a noun, grande means big or large but when it precedes a noun, it means great.

Un gran concierto --- Una gran fiesta 
 
Un auto nuevo 
 = a brand new car 
 
Un nuevo auto 
 = a new, different car 
 
Un hombre grande 
 = a big man 
 
Un gran hombre 
 = a great man 
 

g) Santo is shortened to San when it precedes proper masculine names.

San Cristobal --- San Antonio 
 
San Idelfonso --- San Juan 
 

Exceptions: Santo Tomás, Santo Toribio and Santo Domingo

h) Ciento is shortened to cien when it precedes a noun

Cien coronas --- Cien pesos