Describe the ways in which the story generates suspense. At which points is an increase of suspense particularly noticeable?

Oates builds suspense in the story through her style of writing.  The story is written in a casual tone.  Because of this, the realizations by Connie that she is in grave danger become even more striking.  The way that Oates describes how Arnold Friend casually talks to Connie and the way he works his way into the home helps add suspense, for example.  There is no rushing, no grabbing, no urgency about the story, until Connie suddenly realizes she needs to call someone, then can only scream into the phone.  Even then, though, Connie realizes that it is useless to fight Arnold Friend.  She realizes she is as good as dead and simply walks out of the door to her home on her own in a dreamlike state of disbelief:

In fear, Connie stumbles her way to the phone but is unable to dial; she simply screams into the receiver. When she stops, Arnold is standing by the door. Her fear is replaced by emptiness, and she understands that she will leave the house and never return. She approaches the screen door and watches herself opening it, feeling as if she no longer inhabits her own body. She walks out into the sunlight where Arnold waits, assuming a mocking gesture of welcome.

This is the way Oates ends the story...with a tone of foreboding evil and horror because the reader does not know what Friend will do to poor Connie.  All the reader can surmise is that she will be dead before too long.