what tequniques did alfred hitchcock use for shadow of a doubt to create suspense

At the telegraph office she learns that he has just announced by telegram that he is on his way. At times she feels the charming man is the only one who understands her need to be extraordinary, that there is more to her than her small town allows. She not only shares a nickname with her mother's youngest brother, but a special bond.

Charlotte decides to improve things by inviting her favorite Uncle Charlie to come for a visit. Charlotte 'Charlie' Newton (Teresa Wright), is frustrated by boredom, complaining to her father, Joseph 'Joe' Newton (Henry Travers) because nothing interesting ever happens in her life or that of her family. In Santa Rosa, a teen living in a two story house is lying in bed. Oakley is at a pay phone booth, sending a telegram to Santa Rosa, California, telling his sister that he is coming for a visit and will arrive in a couple of days. He walks quickly, turns corners, loses them as he goes up a building and watches them from the rooftop, making sure he has lost them. Spencer, whose real name is Oakley, gets off the bed, picks up the money, goes out past the men, who do not react, but begin to follow him at a distance. Spencer' (Joseph Cotten) that two men were asking for him but she had followed his instructions, told them he was out. The landlady, Mrs Martin (Constance Purdy) knocks, opens the door and tells 'Mr. Money bills are on his dresser and tumbled on the floor. A man dressed in a suit is lying on a bed, deep in thought. Couples in costumes in a room with 1900 décor are dancing to the music of The Merry Widow waltz by Franz Lehar.

What tequniques did alfred hitchcock use for shadow of a doubt to create suspense