This is a tough question since I'm not sure if it is asking how to begin to write a novel, but that is what I will answer. Of course, the broader response is: NEVER GIVE UP! I know I sound like Winston Churchill!
I have a friend that tells me she wants to write, and she starts, and she stops! I tell her my advice is like the Nike commercial - just do it! I think she is too self-critical, and believes if the first few pages aren't perfect she shouldn't continue. How you begin a story doesn't mean it can't be changed! It will not be perfect - you may think of a better way to begin the story as you delve deeper. Before I start the first paragraph, I have an outline, and have already developed my characters and understand their motivations. I know them so well that I can tell you what they had for dinner! That seems to work for me.
Write a few chapters, set it aside for a few days and then read it again. If it is interesting to you, chances are it will be interesting to others. Ask the opinion of those that you know will tell you the truth, not what you hope to hear! Granted, that will be difficult, so try not to ask family members!