I often find starting a new book to be the most challenging part. Once I get into the second or third chapter, I feel oriented as to what the book is about and where it's going, and I want to continue reading to see how it turns out. But the first chapter or two can take effort to pull myself through.
But also, be sure to select books you really think you will find interesting. I have surely read some best sellers, but I did not end up selecting them because they were best sellers. Perusing the current NYT best seller list, I see a few books that I might be interested in reading, but frankly, I have stacks of other books waiting to be read that appear more interesting to me.