So I recently finished Beginnings, Middles and Ends by Nancy Kress, an award-winning author who teaches writing. In her book, she discusses weaknesses in those three areas and how to improve each one. I share some of her ideas on the beginning of a novel with you here.
The first sentence of one's novel needs to be unique and grab the reader's attention. The first scene should introduce at least one character, a conflict, be specific in detail, and credible. It has to be interesting enough that the reader will want to read on. It shouldn't be generic but original, demonstrating that your book is different than others and special in some way. In the beginning of a story, one wants to set up a conflict via an event or situation. It might be a problem or mystery that the protagonist has to solve. Details and building engaging characters will give one's story more believability.
The first chapter may set up a promise. If someone is murdered, the reader wants the crime to be solved and/or shown what lengths the detectives or others go to in order to find the killer. If a girl meets a boy, the reader expects a romance to fulfill that promise. If a character is conflicted within himself, battling with a conscience or inability to act, the reader wants to see the character go through a transition for better or worse. The promise doesn't always mean a happy ending, but a journey that explores, inspires or brings the reader to a different place then where he started. It doesn't necessarily need to be a lesson learned but shed a different perspective or give an insight into human nature.
Those are just a few examples from this great book on writing. I encourage you to read it if you are a struggling writer or if you are new to writing stories.