Entry point is where your story begins... When we crack the book open and read the first page, what is your character doing?
Do we begin at the beginning? "In a hole in the ground there lived a hobbit. Not a nasty, dirty, wet hole , filled with the ends of worms and an oozy smell, nor yet a dry, bare, sandy hole with nothing in it to sit down on or to eat: it was a hobbit-hole, and that means comfort." In The Hobbit, J.R.R. Tolkien begins by explaining Bilbo to the readers. It is our first encounter with a hobbit after all. Through the first chapter, as the action unfolds, Tolkien characterizes Bilbo so solidly that we end up with a vibrant picture and well-defined expectation of what Bilbo is like. And then he does something unexpected. The adventure is just about to begin... and what an adventure!
Are we in the middle of the action? "My husband’s mistress leveled the gun at me. Her perfect, blonde curls bounced as she took a firing stance in the doorway to the conference room. Our eyes met over the gun, and the alien clone holding me, hitched up my arm to use me as a shield. The clone adjusted the quiack knife against my neck to make sure I knew he meant it. My husband’s mistress, Trish, puffed her bangs out of the way and squeezed the trigger." This was the beginning of a novel written by my blogging friend, the amazing and talented Rena. I won't go into the reasons why she changed her entry point, but this, as one of her previous options, illustrates the idea of jumping RIGHT into the action. We learn a lot of details rather quickly about the characters and have immediate tension and excitement to draw us further into the story.
Does the narrative start in the past (to set the stage) and then jump to the present? The best example of this is still Harry Potter and the Sorcerer's Stone Chapter 1. Other examples frame this kind of entry point as a prologue. Example: Seraphina by Rachel Hartman, "I remember being born. In fact I remember a time before that..." Depending on the amount of back story you need to set up your reader's understanding of the current action, this can be a good idea... or it can be a bad idea. If the information in a prologue needs so very much to be part of the story, you might want to consider ... making it part of the story!
Entry points can and do change over the course of drafting and revising. Sometimes skipping the set-up and heading straight for the action is the best thing you can do to jump-start a lagging narrative. Other times the set-up, artfully done, is required to help attach your reader to the main character. How does the current entry point of your WIP set the stage for your novel?