This post is not meant to beat down on the newbies, but to help those who are in the same boat I was when first seeking representation for my writing. I made a lot of rookie mistakes and am still learning. I've come to realize agents and editors can spot an amateur from page one. Not that rules aren't meant to be broken from time to time, but give your manuscript a fighting chance of passing the newbie sniff test when submitting.
1. Don't overdose on adverbs. Drat that "LY." Your character might "run quickly up the hill," but your reader would be even more interested if your character "sprinted up the hill." Try to eliminate adverbs and, instead, use a more interesting verb. If Beth speaks softly, she could probably whisper just as easily. If Frank dances wildly, Frank gyrates. You get the picture?
2. Don't incorrectly punctuate dialogue. If you're an avid reader, you HAVE to have some idea how to punctuate dialogue, or you haven't been paying attention. If dialogue is NOT punctuated correctly, the reader (agent or editor) will notice. It's a huge neon sign pointing to inexperience. Pick up your favorite novel and analyze how the dialogue is punctuated and copy the format in your own writing OR check my previous posts for demystifying dialogue.
3. Don't get fancy with dialogue tags. A dialogue tag is the "he said" of a quote. It explains who is doing the talking. Although we discussed in #1 how to eliminate adverbs by using more interesting verbs, when it comes to dialogue tags, it's best to keep it simple. He says. She says. He said. She said.
"I hate your dress!" yelled Frank.
"Well, you're an awful kisser!" shouted Beth.
Frank begged, "Please cover up that cleavage."
"Fine," Beth retorted, "if you brush your teeth and eat a bag of breath mints."
**Yes, it's fun to throw in those cool verbs, but they distract from instead of enhance what is being said. The dialogue tag should really just tell who is talking, not upstage what is between the quotation marks.
"I hate your dress!" said Frank.
"Well, you're an awful kisser!" said Beth.
Frank said, "Please cover up that cleavage."
"Fine," Beth said, "if you brush your teeth and eat a bag of breath mints."
4. Don't provide the extras. Until you have a publishing deal in place, do NOT include a dedication page, cover art, decorative fonts, etc. It practically broadcasts you are a newbie. One exception might be the inclusion of a map of the setting if, and only if, it is really necessary to understand the story. Even then, I don't recommend providing one until an agent or editor asks for a full manuscript.
5. Don't overdose on character description. You want your reader to know what your character looks like, but too much detail will slow down the manuscript and give readers no chance to form their own personal, mental picture. Allow readers to fill in a few of the blanks. Sure, if your main character has a very specific characteristic that adds value to that character or is important to the story line, by all means, include it. A full description from head to toe, upon introducing said character, is unnecessary.
6. Don't randomly jump from one point of view to another. Called "head hopping," jumping from one point of view to another is frowned upon, unless it is VERY well done and clear to the reader who is doing the thinking. For instance, a classic example of varying points of view would be the very popular "Game of Thrones" series, in which each chapter is from a different point of view. Fortunately, the author makes it very easy on the reader by using the name of the character as each chapter's header.
7. Don't neglect to proofread ... thoroughly. Many new writers think it is an agent's or editor's job to "sweat the details." Realistically, agents and editors receive hundreds of submissions each month. Don't give them a reason to reject your manuscript. It should be as clean as possible and free from errors. If you are a writer who doesn't have strong proofreading skills, consider paying someone who DOES, before you start submitting to agents or editors.
Good luck and welcome to the party, newbie!