How does Ibsen present the characters and through what techniques?

Nora
Nora is presented at the beginning as a woman with a perfect life. "Is that my little skylark chirruping out there?", "Is that my little squirrel frisking about?" Nora is cherished by her husband as he refers to her as cute, little animals and Nora seems to be perfectly fine with this as she replied excitedly "yes!" to his every questions. The image of a squirrel presents Nora as herself well "She stuffs the bag of macaroons in her pocket". As we all know, squirrels' nature is to collect and hide their food for later needs. This foreshadows the later events in the play when it was revealed that Nora had been working and "collecting" bits of money to pay back the debts. Although she has to face all of the financial worries, Nora is still a fairly childish character as she likes to eat macaroons which are sweet, colorful treats that kids like and she hums to herself throughout the first part of the scene which makes the audience think that she has no significant worries at all.

Torvald

In a doll's house by Ibsen, Torvald Helmer was portrayed as a typical 19th century man whose pride was a compulsory personality trait. The phrase "No debts! Never borrow!" shows that Torvald's mind is very fixated on the idea of keeping his reputation no matter how bad the situation is, in this case, as we later on find out, his serious illness. Torvald is also depicted as a dominating character as he dehumanized Nora "Is that my little skylark.... my little squirrel frisking about". Helmer also treats Nora as a child by taunting her about spending money ( "my little spendthrift" ). Ibsen uses these examples of dominance to clearly portray Helmer to be symbolic of the 19th century husband.

Mrs. Kristine Linde

Mrs Kristine was portrayed by Ibsen as a foil to Nora as she is quiet and direct "Yes, it's me", "No". The structure of her replies are very short and direct compare to Nora's which shows that she is not as frivolous. She'd rather answer what she's been asked than adding on to the flow of the conversation.