Frankly, a discussion of how to get published is not worth much if you cannot write well in the first place.
Here are two suggestions if you want to improve your writing:
1. Read this collection of quotes on "20 Great Writers on the Art of Revision," and get the principle clearly fixed in your head.
2. Buy, read, and apply Joseph Williams's Style: The Basics of Clarity and Grace. (There's a guidebook/workbook as well.)
Here is a summary of the main points:
Ten Principles for Writing Clearly
1. Distinguish real grammatical rules from folklore.
2. Use subjects to name the characters in your story, avoiding abstractions.
3. Use verbs to name characters' important actions, identifying actions and avoiding nominalizations.
4. Open your sentences with familiar units of information, utilizing introductory fragments and subordinate clauses at the beginnings of sentences.
5. Get to the main verb quickly:
- Avoid long, complicated introductory phrases and clauses.
- Avoid long abstract subjects.
- Avoid interrupting the subject-verb connection.
6. Push new, complex units of information to the end of the sentence, providing transitions to get to them.
7. Begin sentences constituting a passage with consistent topic/subjects.
8. Be concise:
- Cut meaningless and repeated words and obvious implications and clichés.
- Put the meaning of phrases into one or two words.
- Prefer affirmative sentences to negative ones.
9. Control Sprawl:
- Don't tack more than one subordinate clause onto another.
- Extend a sentence with resumptive, summative, and free modifiers.
- Extend a sentence with coordinate structures after verbs.
10. Above all, write to others as you would have others write to you.
Ten Principles for Writing Coherently
1. In your introduction, motivate readers to read carefully by stating a problem they should care about.
2. Make your point clearly, the solution to the problem, usually at the end of the introduction.
3. In that point, introduce the important concepts that you will develop in what follows.
4. Make it clear where each part/section begins and ends.
5. Make everything that follows relevant to your point.
6. Order parts in a way that makes clear and visible sense to your readers.
7. Open each part/section with its own short introductory segment.
8. Put the point of each part/section at the end of that opening segment.
9. Begin sentences constituting a passage with consistent topic/subjects.
10. Create cohesive old/new links between sentences.
If you find this kind of checklist helpful here's another list, this one from Roy Peter Clark's book, Writing Tools: 50 Essential Strategies for Every Writer:
I. Nuts and Bolts
1. Begin sentences with subjects and verbs.
Make meaning early, then let weaker elements branch to the right.
2. Order words for emphasis.
Place strong words at the beginning and at the end.
3. Activate your verbs.
Strong verbs create action, save words, and reveal the players.
4. Be passive-aggressive.
Use passive verbs to showcase the "victim" of action.
5. Watch those adverbs.
Use them to change the meaning of the verb.
6. Take it easy on the -ings.
Prefer the simple present or past.
7. Fear not the long sentence.
Take the reader on a journey of language and meaning.
8. Establish a pattern, then give it a twist.
Build parallel constructions, but cut across the grain.
9. Let punctuation control pace and space.
Learn the rules, but realize you have more options than you think.
10. Cut big, then small.
Prune the big limbs, then shake out the dead leaves.
II. Special Effects
11. Prefer the simple over the technical.
Use shorter words, sentences, and paragraphs at points of complexity.
12. Give key words their space.
Do not repeat a distinctive word unless you intend a specific effect.
13. Play with words, even in serious stories.
Choose words the average writer avoids but the average reader understands.
14. Get the name of the dog.
Dig for the concrete and specific, details that appeal to the senses.
15. Pay attention to names.
Interesting names attract the writer---and the reader.
16. Seek original images.
Reject cliches and first-level creativity.
17. Riff on the creative language of others.
Make word lists, free-associate, be surprised by language.
18. Set the pace with sentence length.
Vary sentences to influence the reader's speed.
19. Vary the lengths of paragraphs.
Go short or long --- or make a "turn"- to match your intent.
20. Choose the number of elements with a purpose in mind.
One, two, three, or four: Each sends a secret message to the reader.
21. Know when to back off and when to show off.
When the topic is most serious, understate; when least serious, exaggerate.
22. Climb up and down the ladder of abstraction.
Learn when to show, when to tell, and when to do both.
23. Tune your voice.
Read drafts aloud.
24. Work from a plan.
Index the big parts of your work.
25. Learn the difference between reports and stories.
Use one to render information, the other to render experience.
26. Use dialogue as a form of action.
Dialogue advances narrative; quotes delay it.
27. Reveal traits of character.
Show characteristics through scenes, details, and dialogue.
28. Put odd and interesting things next to each other.
Help the reader learn from contrast.
29. Foreshadow dramatic events or powerful conclusions.
Plant important clues early.
30. To generate suspense, use internal cliffhangers.
To propel readers, make them wait.
31. Build your work around a key question.
Good stories need an engine, a question the action answers for the reader.
32. Place gold coins along the path.
Reward the reader with high points, especially in the middle.
33. Repeat, repeat, repeat.
Purposeful repetition links the parts.
34. Write from different cinematic angles.
Turn your notebook into a "camera."
35. Report and write for scenes.
Then align them in a meaningful sequence.
36. Mix narrative modes.
Combine story forms using the "broken line."
37. In short pieces of writing, don't waste a syllable.
Shape shorter works with wit and polish.
38. Prefer archetypes to stereotypes.
Use subtle symbols, not crashing cymbals.
39. Write toward an ending.
Help readers close the circle of meaning.
IV. Useful Habits
40. Draft a mission statement for your work.
To sharpen your learning, write about your writing.
41. Turn procrastination into rehearsal.
Plan and write it first in your head.
42. Do your homework well in advance.
Prepare for the expected --- and unexpected.
43. Read for both form and content.
Examine the machinery beneath the text.
44. Save string.
For big projects, save scraps others would toss.
45. Break long projects into parts.
Then assemble the pieces into something whole.
46. Take interest in all crafts that support your work.
To do your best, help others do their best.
47. Recruit your own support group.
Create a corps of helpers for feedback.
48. Limit self-criticism in early drafts.
Turn it loose during revision.
49. Learn from your critics.
Tolerate even unreasonable criticism.
50. Own the tools of your craft.
Build a writing workbench to store your tools.