You can read the first sentence – or the first paragraph or scene – to see if you like a book. That sounds like a logical strategy, kind of like tasting a flavor of ice cream before buying it.
But the book makers know that at least some readers use this strategy. So they sometimes construct as interesting of first line or scene as they can, aparently without much worry about how that hyper-interesting start influences the quality of rest of the book.
That hyper-interesting start will probably push events out of chronological order; it might spoil upcoming scenes; it might make a scene worse. That first line can even just be wrong. And there are other problems.
So I want you to know when that strategy is being used on you. The goofy first lines are not difficult to spot. Sometimes they actually seem goofy. Usually, the next sentence will be out of chronological order. Maybe the first line reveals the future.
Prologues usually are in the same category. If chapter 1 begins in a time before the prologue, that's a bad sign.
It turns out that if a book begins with what I call an action start, I'm more like to enjoy that book than if it begins with any other kind of start. That isn't as reliable as the average weather report, but it's a reasonably good indicator. For me.
To be clear, I like action starts more than description, but this indication works for the whole book, not just the start. It's as if the author has a way of thinking about things, or writing them, or presenting them, that fits with what I like to read.
I can't tell you what are good indicators for you. These webpages will talke about different things that happen in starts. Then you can decide.
There is a problem of patience. To take an extreme, one style of start is "life as normal". The author should make that interesting, but it still isn't the real story with the real interest. The author chose that start (HOPEFULLY!) because it's the best for your reading experience. If readers bail out from those, then those starts don't get used and our books are not as good as they could be.
More mundanely, the starting scene lacks context, so it can't be as interesting as if it was placed later in the book. So there is a limit on how interesting that first scene can be. Of course, the author can partially combat this by choosing an interesting scene to start the book, but that's the hyper-interesting start that causes problems, as discussed above.
One of my favorite books ever began with one of the goofiest first lines I have ever read:
My brother is the king of nowhere. (Tyrant's Daughter)
I laughed at the first line, set the book down, and just happened to pick it up later. Except for that first line, it's a great book, and by the end of the book that line even made sense. (Of course that's not when sentences should first make sense.)
So, that's a little story suggesting some tolerance for goofy first lines. Or why they shouldn't be in books.
So, there's reasons to be patient. And reasons to bail. I hope you can learn a little more about starts, so you can better tell the two apart. It's a tough call. But, in my opinion, an author should be able to make any start at least as little interesting. So complete boredom is a bad sign.
Looking for Quality
In theory, you can look for quality. Um, that's not easy to do; most readers just read.
One thing to look for is if the main character is "coming alive". The characters should seem to have different personalities, not the same personality in different bodies. Some authors provide more descriptive detail than others, so you can judge a book on if it has the amount of detail you like.
Hooks are things that make you keep reading to learn something, such as who the murderer is or if the the main character lives. They work even if the book isn't enjoyable to read.
If you aren't enjoying your reading experience, and you are hooked, skip to the end. Or ahead. If you like hooks, then you can judge a book on the strength of the hook.
Sometimes the back of the book has recommendations, like from other authors. They're always positive. If you find an evaluation on the back of the book that makes you want to read the book, that's good writing by whoever is making the evaluation.
Often, the back of the book (or the inside jacket) contains a description. I will call that the blurb.
The blurb is designed to get you to read the book. It has even more spoiler potential than the prologue and goofy first line. In fact, the author has probably thought about how the book should be read while assuming you don't read the blurb.
I once read a book by a very famous author, and it wasn't good. The characters weren't good, they behaved implausibly, I couldn't follow things at the start, and the ending was very disappointing. I thought, as I always do, that the author must be doing something right to be that famous. And indeed I could find things the author had done right.
Then I read the blurb for the book. Everything the author had done right was in the blurb! (Plus one other good thing I hadn't thought of.) Yes, one small blurb had it all. That author writes outstanding blurbs.
First issue: Starting with setting versus action.
Skipping ahead to a page that would specifically concern readers: