Expressive means and stylistic devices

The author’s expressive style is created with the help of lexical expressive means and stylistic devices. They help a reader to understand the characterization of characters and the plot itself more vividly.

The metaphor bulldozing the grocer and the vegetable man and the butcher is used to underline how difficult the financial situation was and that Della didn't not just bargain but she did it insistently.
The repetition of the adjective grey  She stood by the window and looked out dully at a grey cat walking a grey fence in a grey backyard is used to show how hopeless situation seemed to be, and Della was disappointed because she made every effort and her savings were little.
The simile is used to describe Della’s greatest possession - her hair Della’s beautiful hair fell like a cascade of brown water. Such simile means that Della could be proud of her hair as not every woman has such beautiful hair.
The inversion  and anaphora are used to point out that her clothes is also poor On went her old brown jacket; on went her old brown hat.
After selling her hair, she became happy as she had enough money to buy the present to her husband, her mood is described with the help of the metaphor next two hours tripped by on rosy wings. The chain to the watch had to be perfect, because Jim's watch were very wonderful and valuable, it is pointed out due to the capitalization The Watch.
The anticlimax and repetition of the conjunction nor It was not anger, nor surprise, nor disapproval, nor horror, nor any of the sentiments that she had been prepared for are used to show that Della is nervous as she is afraid not to be loved by Jim.
The repetition in the sentence You don't know what a nice-what a beautiful, nice gift I've got for you is used to show that Della feels nervous and doesn't know what to say and how to behave.
The antithesis  And then an ecstatic scream of joy; and then, alas! a quick feminine change to hysterical tears and wails is used to underline that Della's emotions were double meaning.
Such epithets as dim eyes, serious sweetness, eyes were shining brilliantly are used to underline the mood of the main characters as it is described indirectly.
The hyperbole Maybe the hairs of my head were numbered," she went on with a sudden serious sweetness, "but nobody could ever count my love for you is used to show how great their love is and it's really boundless.
Colloquial and informal words bulldozing, oh. ain`t I, dandy; detached constructions Her Jim.; simple sentences I buy hair. Cut it off and sold it. are used to make the story true to life, easy to understanding and more expressive.

Characters of "The Gift of the Magi"

The main characters of this story are Mr. and Mrs. James Dillingham Young. These two poor young but so happy people are described indirectly. 

The metaphor bulldozing the grocer and the vegetable man and the butcher until one's cheeks burned with the silent imputation of parsimony that such close dealing implied is used to show how strong Della is and that she is ready for everything to buy a worth present to her husband. She is a wise and thrifty woman .The metaphor her eyes were shining brilliantly means that despite all problems and lack of money, she was happy as she loved and was loved. 

She was a beautiful woman and her hair was splendid it's proved by the use of simile Della's beautiful hair fell about her, rippling and shining like a cascade of brown waters and hyperbole It reached below her knee and made itself almost a garment for her. 

The inversion on went her old brown jacket; on went her old brown hat underlines the poverty of her clothes, but it wasn't the most important thing for her. 

The simile curls that made her look wonderfully like a truant schoolboy is used to show that she didn't become to look more wonderful, but she sacrificed her beauty in order to buy the present for her darling. 

Jim, Della's husband, was a very serious and reserved man and it's proved by the use of simile as immovable as a setter. The word stare is used instead of look to underline that he was puzzled and tried to realize the situation quickly but couldn't "He simply stared at her fixedly with that peculiar expression on his face". 

To relieve the tension and not to spoil a holiday, Jim used an adverb too "They're too nice to use just at present", which creates a humorous effect.

The main characters are very sincere, generous and kind-hearted. Their love is ready for everything and due to their wisdom they are compared to Magi.

And here I'd like to present you the plot of this story in pictures. I find it interesting and hope for you it will be also interesting! 

“When you love you wish to do things for. You wish to sacrifice for. You wish to serve.”
 ― Ernest Hemingway, A Farewell to Arms

The plot of the story and types of speech employed in it

The introduction of the story is the 3d person description of a poor flat where the main characters live. The story is about a young married couple - Jim and Della. They live in a cheap flat and don't have enough money for buying presents for Christmas.They have only two treasures - Jim's gold watch that had been his father's and his grandfather's and Della's beautiful hair which reached below her knee. 

Della decided to sell her hair in order to buy a chain on Jim's watch. She is very happy, but she is afraid whether Jim will appreciate her sacrifice and love her with short hair. The third person narration is combined with the elements of a dialogue and interior monologue. 

The climax of the story is when Jim presents combs to Della, but now her hair is short. The reader can assume where Jim got money for buying the combs. Jim is also shocked by Della's present as doesn't need a chain any more.

The anticlimax is "Dell," said he, "let's put our Christmas presents away and keep 'em a while. They're too nice to use just at present. I sold the watch to get the money to buy your combs. And now suppose you put the chops on."

The conclusion of the story is written as the 1st person narrative by the author, who compares main characters to the magi as they are the wisest.

The setting of "The Gift of the Magi"

The events primarily take place in the characters' flat. O. Henry describes the apartment where Jim and Delia live.The description is detailed but not to make the reader take pity on the characters, but  understand the great sacrifices Delia and Jim made. The capitalization in the first line is used to show how difficult financial situation in the family is ONE DOLLAR AND EIGHTY-SEVEN CENTS. THAT WAS ALL. AND SIXTY CENTS of it was in pennies.
Such epithets as shabby couch, beggar description and mendicancy squad are used to underline that the flat is cheap and poorly furnished, but they are happy living there because their feelings are true and they make that flat pleasant and brighter for them. To show how Jim is important for Delia, the author uses a possessive pronoun before proper name - Only $1.87 to buy a present for Jim. Her Jim. 

The mood of the story is sad and disappointed, it is proved by the repetition of grey  -  a grey cat walking a grey fence in a grey backyard. From the color symbolism I got to know that "Gray can stifle and depress energy but it is also the stable base from which the new and positive can come". It means that in spite of all difficulties, miracle will come.

The events take place just on Christmas Eve, that makes story in some cases mysterious because everyone expects the miracle. And everyone prepares gifts to the close, Jim and Delia did the same in spite of their small income. The strong Delia's desire to make her husband happy and to present him a gift is underlined by the use of an indefinite article 'a' after an adverb 'many'  - Many a happy hour she had spent planning for something nice for him. 

The setting of “Gift of the Magi” likely reflects O. Henry’s location at the time in New York City. In 1906, New York was still a shipping city, bustling and packed. There were no skyscrapers yet, and South Street was still an important commercial district rather than the tourist attraction it would become by the end of the century.