Another thing I frequently find myself writing on students' work is, "Don't pull its teeth!". Here, "it" is a scene, a sentence, a character's thought, or a character's action, which has all the ingredients to be compelling, but somehow falls flat. (Actually, I usually write "Don't draw its teeth" which is the phrase I grew up with. But I wouldn't want you to think we were talking about keeping your sketchbook closed.)
Don't pull the teeth of a thought. This is probably the most common, and I think it stems from the first-drafting writer very naturally mulling over all the possibilities, so they all end up on the page:
Leela gazed at the postcard. Maybe she should just buy a plane ticket to Granada? But that was probably a bad idea. Jim very possibly would still be in New York - and if he was, he would almost certainly be a bit annoyed with her for showing up on his doorstep with only an hour or two warning. No, that really did seem like a bad idea - and it would be rather expensive, too. She probably shouldn't spend that kind of money on just a hope.
See how each action that Leela thinks of - and the reader grabs hold of - is negated? See how many maybe, possibly, almost, a bit and other diluting words there are? In real life we weigh probabilities and opposing arguments, but in print you don't want every move forward to be immediately countered or attenuated. Even if, in the end, Leela isn't going to go, you need to give us the forward-energy first - and only slam on the brakes once they'll have real effect:
Leela gazed at "Sunset Over the Alhambra". She could just buy a ticket to Granada and go. Why not? Cut to the chase, show up on Jim's doorstep, sort it all out before he had time to get angry. Done.
Except that he was probably still in LA. And she could no more afford a plane ticket to LA than she could afford one to the moon. It was hopeless.
Notice how the paragraph-break after Done gives the apparent finish of the thought a moment to resonate before you put the boot in. Notice, too, the one probably which still gets in there - because Leela genuinely can't be sure.
Don't pull the teeth of a sentence. We've seen how maybes and possiblys can weaken the thinking, but there's a different kind of weakening which happens when a writer is - paradoxically - trying to be more exact. I go on about how being specific and particular (scroll down a bit) is usually the best way to fire up the reader's imagination, but there's also the style of sentence which Stephen Pinker calls CYA - which (being better brought up than me) he says stands for "cover your anatomy" - and sometimes "compulsive hedging".
It's the nervous kind of exactitude which must qualify everything, or explain everything, in case you're caught out exaggerating or getting things "wrong" - hence my sense that it's particularly common in historical fiction and other stories resting on researched material.
In the bay, seven boats of varying sizes were drawn up on the very large beach, which looked rather more like shingle than sand.
Big boats and tiny ones were drawn up on the bay's wide crescent of sandy shingle.
Notice also the looked, which is a classic bit of filtering. Now try this one:
She is very helpful, but it's extremely obvious to him that only her strongly-felt desire to be really thorough keeps her picking almost obsessively at the carpet even after they'd surely found all the broken glass. Though it's very likely that she doesn't want to talk about Dan, of course.
Long after they've found all the glass, she keeps on picking helpfully, even obsessively, at the carpet. Or does she not want to talk about Dan?
Don't pull the teeth of a scene. If you bring the picnic scene to the climax of the row, the proposal, the murder or the eureka moment - don't let everyone then just pack up and depart unchanged. These events have consequences (if they don't, why are they in the novel?) so make sure they resonate through what follows, proportionately to their importance.
Indeed, what you thought was the climax may in fact be the midpoint: the point when the characters must act, after which nothing can ever be the same. If so, don't short-change the reader of that. Alternatively, you could cut immediately after the big bang - and let the possible consequences ring in the reader's head over the chapter-break. (Just bear in mind that this trick gets very wearisome, and the law of diminishing returns soon sets in.)
My long-ago choir director used to say, "From being a mezzoforte choir, may the good Lord deliver us". Musically, "moderately loud" is chiefly useful as a jumping-off point for music which is about to do something more definite. It's choirs who don't trust themselves who get stuck at mezzoforte level, too uncertain to commit - and in turn the audience can't relax either. Similarly, readers experience writing as confident, and relax into the story, when the writer does things wholeheartedly, without hedging, losing their nerve, or letting their writing draw their storytelling's teeth.
So, if you've realised things are too mezzoforte for too long, the solution is usually to go for either more, or less: either forte or piano. Either put Leela through the flaring hope of sorting things out with Jim - and then swipe her with the denial of that hope - and then move on. Or, if Leela's ditheriness is central to who she is and to what powers the narrative drive, you could do the ditheriness forte: not just a series of toothless probablys and possibles and things briefly raised and easily dismissed: make the dither a series of mounting hopes, each of which is, ultimately and agonisingly dashed.