You could include some of the following points in your essay.
The extract is solely narrative which focuses on description with effective use of adjectives, adverbs and descriptive phrases to reveal Scrooge’s character.
The writer uses the omniscient narrator to reveal the character of Scrooge through description.
The writer uses diction associated with coldness and hardness to reveal the character of Scrooge – “the cold within him froze his cold features”, “A frosty rime was on his head”, “Hard and sharp as flint” (simile).
The writer uses a simile to reveal Scrooge’s desire to be alone – “solitary as an oyster”.
The extract begins with a list of onomatopoeicverbs to reveal Scrooges harsh character – “squeezing, wrenching, grasping, scraping, clutching, covetous old sinner!”
The writer opens with a metaphor revealing the hard nature of Scrooge’s character – “he was tight-fisted at the grindstone".
The writer uses pathetic fallacy to reveal the character of Scrooge and show the lack of influence the weather had upon his character – “External heat and cold had little influence on Scrooge. No warmth could warm, no wintry weather chill him. No wind that blew was bitterer than he”.
The writer uses sounds to create an unpleasant, cold atmosphere – “the people in the court outside go wheezing up and down, beating their hands upon their breasts, and stamping their feet upon the pavement stones to warm them”.
The writer reveals that other characters avoid Scrooge – “Nobody ever stopped him in the street”, “no man or woman ever once ... inquired the way”, “Even the blind men’s dogs ... would tug their owners into doorways”.
The writer uses pathetic fallacy to create a desolate and stark atmosphere in the extract – “It was cold, bleak, biting weather”, “The fog came pouring in at every chink and keyhole”.
The writer uses Scrooge’s treatment of the clerk to reveal his mean character, "Scrooge had a very small fire, but the clerk’s fire was so very much smaller that it looked like one coal.”