Quote 1
"I want to attempt a thing like that and am frightened by these trifles," [Raskolnikov] thought, with an odd smile. (1.1.5)
This is the first time we hear about Raskolnikov's bad idea. Even though most people already know the book is about a murder before they read it, it's still creepy and mysterious.
Quote 2
[Raskolnikov] was positively going now for a "rehearsal" of his project, and at every step his excitement grew more and more violent. (1.1.9)
Uh-oh. He really sounds like a criminal here. Depending on the crime, rehearsing can get you into almost as much trouble as actually committing it.
Quote 3
"Hey! You Svidrigaïlov! What do you want here?" [Raskolnikov] shouted, clenching his fists and laughing, spluttering with rage. (1.4.14)
Raskolnikov (and the readers) have only heard about Svidrigaïlov by this time. Raskolnikov calling the sketchy man in the park "Svidrigaïlov" foreshadows his presence in St. Petersburg and prepares us for his nastiness.