They use adjectives to describe the characteristics of their character, and when using dialogue they'll sometimes have them use witty remarks or have them be more bland based on the personality that hey wish to convey. Also, an author will, after or before dialogue, add an adjective to what they're saying. For example: "I've been there before" Victor, said casually. Or: Ashley yelled "Well you should have known!" punctuation is also a key element in conveying a character well.
In a realistic novel, the society is the chief concern. Realism usually presents slice of life stories that when further analyzed can be examined for societal norms and behavior and criticism of that time.
