I have recently begun editing my 30k word draft for Hunter Romero and the Atlantean Curse and I've discovered something terrible. Somewhere around half of my sentences are remarkably similar to this, "He fired a shot and heard a cry of agony. He dove down as wood chips flew by him. He leapt back up and ran towards the edge of the ship where he..." and so on. My question is, how do I vary the sentences so they don't all start with he?

I'd do something like this:

He fired a shot and heard a cry of agony, wood chips flew by him as he dove down.

Um, that's a run on. . .

What's a run on? Is it bad?

http://www.merriam-webster.com/dictionary/leapt

Merriam-Webster claims that is leaped or leapt, and leapt also flows better.

I humbly accept your surrender.

Now, back on topic. Does anyone know any references on sentence structure that I can use?

When every sentence structure falls into the same old “Subject Verb Object” mold, writing starts to sound monotonous. This needn't be the case; English syntax is flexible, and lets you play with sentence structure variations to create word music.

Positions of Emphasis
When you read a sentence, the parts most likely to catch your attention and stay in your mind are the beginning and end; we call them the positions of emphasis, with the stronger position at the close of the sentence.
Writers call attention to important ideas by putting them at the beginnings and ends of sentences. This makes it easier for readers to grasp the meaning and remember important points. It also gives sentences a rhythmic flow, as in these examples:

Mary had a little lamb.

Why didn't they ask Evans?

Ask and you shall receive.

Variations in Climactic Order
Another way of calling attention to key ideas is by placing them in climactic order: that is, arranging them in order of increasing importance or impact. This arrangement builds up suspense in a sentence.

What you choose to emphasize determines your sentence structure. Let's say you want to tell readers about your dog Butterball - a lovely golden retriever, if a little on the plump side (he does so love his food). You could highlight any of these points by leading up to it:

He's gorgeous:
This is my dog Butterball: he's a golden retriever, and you can see he's really beautiful.

He's mine:
This beautiful golden retriever with the slight waddle is my dog Butterball.

He does have a problem, though:
This is my dog Butterball: this greedy little golden retriever that's got to go on a diet.

Repetition Emphasizes Key Elements
You can also emphasize important points by repeating key words or phrases. Repetition links related ideas and gives sentences a lyrical rhythm. For example:

When I was a child, I spoke as a child, I understood as a child, I thought as a child; but when I became a man, I put away childish things.(From The Bible, 1 Corinthians 13:11)

You can repeat pronouns, adjectives, verbs or conjunctions to emphasize key elements and create word music. Repetition also changes the sentence structure and gives it a "piling-on" effect:

Thy rod and Thy staff, they comfort me.

My love is like a red, red rose.

This blessed plot, this earth, this realm, this England,
This nurse, this teeming womb of royal kings...
This land of such dear souls, this dear, dear land,
Dear for her reputation through the world...(From Richard II, Act 2 Scene 1, by William Shakespeare)

In the above examples, the repeated words may seem to add nothing to the meaning - but listen to how they have made the sentences sing.

Combine Repetition with Climactic OrderFor powerful, lyrical language build your ideas up in climactic order, at the same time repeating key words or phrases - as in these examples:

Love is patient, love is kind; love does not envy, love does not parade itself, it is not puffed up; it is not rude, it is not self-seeking; is not provoked; thinks no evil; does not rejoice in iniquity, but rejoices in the truth; bears all things, believes all things, hopes all things, endures all things. Love never fails.
(From The Bible, 1 Corinthians 13: 4-8)

Inversions
If all your words seem to plod along at the same mundane pace, add an element of surprise by varying your sentence structures. One way of doing this is through inversion of word order.

Sentence structures in English usually follow an orderly sequence of subject-verb-object/complement. Any change in this arrangement, like putting the verb before the subject, or the object/complement before the subject, draws attention to itself. Such inversions are especially useful when you want to highlight key words or rev up the tension.

Here are 3 examples of normal sentence structure:

The six hundred rode into the valley of death.
Kubla Khan did decree a stately pleasure-dome in Xanadu.
A child is born to us, a son is given to us.

Sounds flat? How about these "in"-versions:

Into the valley of Death rode the six hundred.
(From The Charge of the Light Brigade by Alfred, Lord Tennyson)

In Xanadu did Kubla Khan a stately pleasure-dome decree.
(From Kubla Khan by Samuel Taylor Coleridge)

For unto us a child is born, unto us a son is given.
(From The Bible, Isaiah 9:6)

Hear the music, feel the excitement in these latter versions? That's the difference inversion makes.

Parallel Structure
Parallel structure, or parallelism, is a special kind of repetition that relies on the balance between related words or phrases to create word music.

You can construct parallel structures by pairing related words or phrases. This balance gives sentences a rhythmic flow and coherence - especially so, where the parallel pairs contain repetitions of the same word or phrase:

It was the best of times, it was the worst of times, it was the age of wisdom, it was the age of foolishness, it was the epoch of belief, it was the epoch of incredulity, it was the season of Light, it was the season of Darkness, it was the spring of hope, it was the winter of despair, we had everything before us, we had nothing before us, we were all going direct to Heaven, we were all going direct the other way...(From A Tale of Two Cities by Charles Dickens)

Note the repetition of it was, we had and we were all going in the example above, and the balanced pairs: the best of times/the worst of times; the age of wisdom/the age of foolishness; the spring of hope/the winter of despair...

Use the rhythm of parallel structures to help you deliver a powerful message to your readers.

Parallel Structure & EllipsesYou can omit words if the meaning remains clear without them; such contractions, known as ellipses, can result in more concise, powerful writing. Ellipses are especially effective in parallel structures, and often give a better balance to sentences:

Homer was the greater genius, Virgil the better artist. In one we most admire the man, in the other the work... Homer, like the Nile, pours out his riches with a boundless overflow; Virgil, like a river in its banks, with a gentle and constant stream.(From Preface to The Illiad of Homer, by Alexander Pope)

Parallel Structure & Climactic OrderUse parallel structures to emphasize key points; present your ideas in a series of balanced words or phrases arranged in climactic order - that is, in order of increasing importance or dramatic impact. Parallel structures in climactic order create the most forceful impression upon readers; as in these examples:

For now we see as through a glass, darkly; but then face to face; now I know in part; but then shall I know fully, even as I am fully known.(From The Bible, 1 Corinthians 13:12)

It is a far, far better thing that I do, than I have ever done; it is a far, far better rest that I go to, than I have ever known.(From A Tale of Two Cities by Charles Dickens)

For it is in giving that we receive; it is in pardoning that we are pardoned, and it is in dying that we are born to eternal life.(From Prayer of St Francis of Assisi)

I'm not very good with poetry.

You might try getting into poetry. I've noticed that after writing a lot of poems and songs, I have a better grasp of how to put words together in just the right way for the moment. Of course, this doesn't mean that you use poetic devices like alliteration and such all through your book, but poetry requires very precise wording, so it's good practice.

@Cassandra: Thank you for posting that article - I just read the whole thing; it was extremely helpful. I'm now going to check out the site

eru

I could recommend some excellent chat tutors on the subject of Poetry.

I've tried poetry, and it flopped.

Poetry and Drabbles are quite lovely... but not exactly pertaining to sentence structure!

Depends on the poetry. If you're writing blank verse, as I usually am, you have to vary your sentence structure, because if you don't your meter won't come out right. In any case, sentence structure is one area of diction, and adhering to the limits and strictures imposed by poetry can strengthen diction in general.

From what I've seen both reading and writing poetry, sentence structure is not only immensely important (rhyming or not) its imperative. Take a look a Tennyson... without the gorgeous structure of his lines his poetry would be nothing. Awesome structure is one of the ingredients that makes poetry really sing.

It's a bit like playing chess to exercise your mind for doing advanced mathematics. There is no math in chess. But the type of thinking required for it is similar. Same story with poetry and drabbles vs. writing interesting and varying sentences.

It's a bit like playing chess to exercise your mind for doing advanced mathematics. There is no math in chess. But the type of thinking required for it is similar. Same story with poetry and drabbles vs. writing interesting and varying sentences.

Sigh. As I said (and Cassandra echoed me in even more general terms), for some (kinds of) poetry this isn't like chess and mathematics, it's like chess and the rules of chess . It isn't a matter of "the type of thinking" being similar between "writing interesting and varying sentences", it's a matter of having to write sentences of varying structure for the poetry to work. To repeat my example, it's simply not possible to write blank verse without at least an instinctive understanding of various kinds of sentences---which is why I primarily recommend reading good, metrically strong, poetry (by which I mean people like, yes, Tennyson, Shakespeare, Spenser, Sidney, even e. e. cummings, more than freer-verse poets like Frost) more than writing it to help improve prose. Your writing sounds (somewhat) like what you read a lot of; reading a lot of poetry with strong diction will help improve yours.