Writers with the best of intentions will include buzz words in their queries that they believe make them look more professional, and, in their minds, will attract an agent's attention. What they don't realize is that for many agents, these phrases and pieces of information more often serve as red flags that this writer has no idea what they are talking about or how publishing works.
Here are the Top 3 self-praises I see:
"I am a published author."
If you have prior publications, you should absolutely list them in your query. Give the title, date, and publisher. Without that information, we have no way to believe you or take this claim seriously. Saying you are a published author when you've self-published or, worse, haven't published at all makes you look foolish.
If you self-published, own it. Tell us when, with who, and for what type of book - then provide sales figures. If you can't give us this information, don't feel that you have to. If your self-pubbed book only sold around 100 copies, it's not the end of the world. Query agents with a project other than the one you self-pubbed and don't feel as if you need to even mention that other book until you receive an offer of representation.
There is absolutely nothing wrong with being a debut author with no prior publishing credits. Being unknown or new to writing will never count against you if you have an amazing book, but having a fake or, let's say, questionable publishing history can end up hurting you if you aren't honest.
"My manuscript has been professionally edited."
The first question that always comes to mind is "by whom?" Your friend who works at the local newspaper? A college writing professor? Your aunt who reads a lot? There are plenty of freelance editors out there whose opinions are professional and whose judgment I would respect as an agent. However, even if you used professional services, there is no reason to say that in your query. It tells me nothing about the quality of your writing or whether I'd be interested in your book. "Professionally edited" is a vague term at best, but at worst it can means one of three things:
1) You think the manuscript is already perfect and you won't be willing to revise.
2) You could be willing to revise, but you aren't able to do it yourself.
3) You think copyediting and editing are the same thing. (This last one I see a lot - the "professional eye" who looked over your manuscript made sure it was polished and grammatically correct, but the character development, plot structure, and overall quality of the writing were still severely lacking.)
Every writer needs an editor, but editors can't make mediocre writing great or make an agent fall in love with a premise. All of that needs to come from you.
"My book has already gotten interest from Hollywood."
On paper, this sounds impressive and I can see why writers include it in their queries. But let's break this down. For one, how does anyone in Hollywood know your book exists? If you're sending manuscripts blindly to showbiz people, not only could your idea could get stolen (and you wouldn't be protected), but it tells me you might be signing contracts and giving away rights that renders any interest I might have had useless (not to mention any deal our film department could have made for you).
The second red flag is that "Hollywood interest" is not impressive to me unless you have an actual contract in your hands from an established production company. There is a huge difference between "Paramount Pictures wants to buy the film rights to my manuscript" and "Larry the coke dealer on Hollywood & Vine said he'll give me $50 for it." Both of these can mean "Hollywood interest," and without knowing the specifics, I assume it's the latter. Plus, think of how many promises are broken in the film industry. Some slick suit who calls you "baby" can tell you he loves your book one minute and then throw it in the trash as soon as you look away.
There is nothing wrong with wanting to make yourself sound more impressive than you think you are. Being a writer is impressive enough in itself, but I understand that in queries you want to add a little more. It's called selling yourself, and this business is all about selling a product. Specifically, your product. But if you really want to impress an agent and get noticed, all you need to do is write the best book you can and know which agent will want to read it.
You should have pride in your work - if you don't, who will? Saying you're "award-winning" even if it was from your local library in 1998 might not change an agent's mind about a project, but hell, you earned it and you should say so. Just make sure you're not inflating yourself so much that you pop.