To make your characters come alive, you have to get to know them. You need to learn their mannerisms and ticks. How they speak. And incorporate that into your story. Once you can do that, you’d have created realistic and interesting characters. Characters that readers would want to want to know more about. Here are some examples.
“I’m bored,” pouted Ty as he tucked his chest and slouched deeper into the couch.
“I’m bbbooooorrrreeeddddd,” drawled his older brother Troy, flailing his arms and his legs until he fell off the couch with a loud bang that almost shook the house.
Look at the dialogue. The same thing is said but in different ways. Which is also followed by two different actions and reactions. With this one scene, the reader is getting lots of information about who Ty and Troy are. That they are brothers and despite the fact that Troy is the oldest he’s the most immature. Also, Ty is a bit of a sulker while Troy obviously is a drama king.
Example 2 (Little Women, Chapter 1):
“Christmas won't be Christmas without any presents,” grumbled Jo, lying on the rug.
“It's so dreadful to be poor!” sighed Meg, looking down at her old dress.
“I don't think it's fair for some girls to have plenty of pretty things, and other girls nothing at all,” added little Amy, with an injured sniff.
“We've got Father and Mother, and each other,” said Beth contentedly from her corner.
Chapter one of Little Women does two things. Introduces the March girls, Jo, Meg, Amy and Beth. And gives readers glimpses of their characters. Jo you can assume to be the least ladylike of the four because she’s lying on the rug. Meg is sensitive about her family’s economic status. Amy is like Meg but considered worse. As she’s portrayed as the easily jealous type wanting what others have. When more than likely, she doesn’t even want it herself. In today’s standards shes' a trend follower. And it’s that nature of her which gets her into trouble at school later in the story. And then you have dear soft-hearted Beth who is the mama’s girl. And daddy’s-sister’s-family’s girl.
Example 3 (Harry Potter and the Sorcerer’s Stone, Chapter 2):
“Thirty-six,” he said, looking up at this mother and father. “That’s two less than last year.
“Darling, you haven’t counted Auntie Marge’s present, see, it’s here under this big one from Mummy and Daddy.”
“All right, thirty-seven then,” said Dudley, going red in the face. Harry, who could see a huge Dudley tantrum coming on, began wolfing down his bacon as fast as possible in case Dudley turned the table over.”
Chapter two fast forwards ten years later after chapter one. After readers learning that Dudley learned a new word, “won’t.” And observing Professor McGonagall’s indignation over Harry Potter living with the Dursley’s. Because she had seen Dudley ‘kicking his mother all the way up the street, screaming for sweets.’ Ten years later and Dudley has not changed. And he is still unbelievably spoiled by his parents. In fact, he has gotten worse because he’s also a bully. Not just at school, but at home as well. Even coercing his parents to get an extra present with the threat of a tantrum.
Words, mannerisms, actions and reactions are indicators of an individual’s character. There was no need to tell that Tyrone was more immature than his younger brother Ty. Or that Christmas for the March family will not be much of a Christmas. Or that Dudley was spoiled. It’s shown through their thoughts and feelings, their body language, mannerisms and dialogue.
For example, would Beth whine about not having the latest fashions? No, Meg and or Amy will complain of such things. You can't have Beth say something un-Beth. It's the same with your characters. Once your character's personality has been established, you can't deviate from it. If you have them say and act contrary to what your readers know of them, they're going to go “huh?” and “where that come from?” And then, they're going pull out from your story.
So in any given scene, you have to place yourself in your characters shoes. Then ask what would he/she say if this happened. What would he/she do if that happened. And then have your character answer/react in what’s consistent to who they are. For additional help, I suggest using The Emotion Thesaurus by Angela Ackerman & Becca Puglisi. As well as the other thesaurus series, such as the The Negative Trait and The Positive Trait Thesaurus at the Writershelpingwriters.net bookstore.
PS The first week and a half of April National Poetry Month has been reserved. I have an interviewee from Japan, the UK and across the US. But I still need more. Hurry and signup to raise the profile of poetry.