This bears repeating because I've been seeing more of this lately. Good story, solid writing, popular genre, even a hook -- but flat in terms of tension. And the problem is, inevitably, that the author is too nice.
You love your characters. I get that -- I love mine too, and the proof of our love is that we spend several hundred hours writing and editing novels about these characters. We lavish them with our time and attention, we pass up television or events in order to spend time with them. We think about them while washing the dishes or driving to the grocery store. You may have bought an article of clothing because one of your characters wears it and then wear it to feel close to that character (**cough**yankeescap**cough**) and maybe you tried a food for the first time because you wanted your character to eat it too.
Okay, so you love the character. Here she is now at a crossroads of her life, and you turn the spotlight onto her and have her work out her problem.
The trouble is that you're too nice. Her problem isn't big enough. Or rather, you the author keep helping her solve it. You can spot these stories because often they open with a world-shattering bang. The main character is in pieces. The main character then spends the next twenty chapters discovering just how many people love her and are willing to help. She tries something risky -- and succeeds! In fact, the stakes are never very high at all after that initial cataclysm. It's as if the writer is nurturing the main character, but at the expense of the story.
Here's something I need to tell you about your characters: they're stronger than you think they are.
Whenever they achieve something, they
must do it by spending some kind of currency they didn't want to spend.
It's their choices that tell you what your character values. If your character goes into the grocery store to buy peanut butter so her kid can eat and sees a jar of Nutella, there's no tension if she picks up both and pays for both.
But if she has only $4, she can't buy both. She needs to make a choice, and her choice is going to tell you about her. She might buy the Nutella for herself and not give her kid the peanut butter. "Sorry, there's only bread tonight." She might buy the peanut butter and be sad about the Nutella. She may lie on the floor in front of the CoinStar machine groping for dropped quarters. She may beg the store manager to let her bag groceries for an hour so she can afford food for her kid. She might decide to steal the Nutella.
Not explode out that kind of small moment and make the overall tension bigger in your own story. What does your character achieve easily that he should achieve by sacrificing something else? If he gets the job of his dreams, maybe he can't continue his college degree. What if she can marry her Prince Charming, but that means leaving her family? Your character should be able to wonder, realistically, if whatever he's achieving is worth what it will cost.
Consider
The Hunger Games. Katniss begins with two things she cannot live without: her sister, and her identity as a survivor. She's immediately faced with a choice, and she chooses to sacrifice the life she knows in order to save her sister. The stakes are immediately set as life-and-death, and with few breaks, they remain that way as Katniss finds over time that even survival isn't something she wants at all cost. In the end, she finds something worth more than even her life.
It's counterintuitive, but if your character's team wins 12-0, it's less climactic than if they win by one run in extra innings...on a hotly contested call, no less.
Quit being nice. Don't fulfill your wishes for yourself by coddling your character. There's a saying that iron sharpens iron, and it's true. Put iron outside your characters and you'll soon find the iron within.
Moreover, we'll have that book glued to our hands if we watch the character keep digging her way out of a pit only to find it's getting deeper and deeper.
Let's say you're writing a novel about a young widow, and your objective in the story is to get her to overcome her family situation to "live again." That's a fairly typical plot, right?
The nice author will show her learning the ropes as a single parent, but with help from her mom and the nice neighbor. Her job will give her time off when needed. Her children will have their struggles, but in general they pull together.
But now you're not going to be nice authors anymore, are you? Instead of being able to rely on her mom, the MC is actually taking care of her mother who's got serious health issues of her own. One of the children is having serious behavior problems. Your MC works for a boss who refuses to cut her any slack for "family time" and threatens to take her job if she clocks out early. She drives a ten year old car with a slipping transmission. In the past her neighbor stayed in check because he was afraid of her husband, but now...
Now you've got a setup. Now you have a fight worth fighting.
Put your main character against the wall, and then keep her there. If the book is 350 pages, then on page 320 the reader needs to believe there's no way out. (In fact, you yourself may be wondering if there's any way out.) Set her wants against each other. Pit her needs against each other. In the first chapter, give her two things she can't live without, and by the end of the book, make her give up the one to save the other.
Maybe she gets them both back in the end, but that's okay. Happy endings are another post. It just needs to be uphill most of the way to "ever after."