Noun Phrases

A noun phrase consists of at least the following elements: a determiner and a noun.

A determiner is one of the following: an article (the, a, an, some, any), a quantifier (none, plenty of, a few, many, etc.), a possessive (my, your, whose, the man's, etc.), a demonstrative (this, that, these, those), a numeral (one, two, three etc.) or a question word (which, whose, how many, etc.).
Except in some very rare cases, a noun can only be preceded by ONE determiner.

A noun phrase can also contain one or more modifiers; a modifier is an adjective, an adjectival phrase, a secondary noun, a prepositional phrase or a relative clause. 

The principal noun in a noun phrase is called the head noun. Adjectives and adjective phrases are placed before the head noun, whereas prepositional phrases and relative clauses follow the head noun.  
Like a noun, a noun phrase can act as a subject, as the object of a verb or verbal, as a subject or object complement, or as the object of a preposition. 

Subject: Masters students often admit that they can’t finish their thesis by themselves.

Object of a verb: To forget quickly and usually is Melissa’s habit.

Subject complement: Neil Armstrong is the name of the astronaut not the scientist.

Object complement: I consider Emma my best friend.

Object of a preposition: The blue whale was found bleary near the beach.