Meet my Hatchet of Death (or, some other colorful description RC Lewis and I come up with at any given moment). This is how I edit myself, it is how I edit others. If you think you want to play with me and my hatchet, shoot us an email.
We all know the first line of a query is your "hook." I call the last line the "sinker." You want it to punch them in the face, in a nice, friendly kind of way that makes them unable to forget you after having read the 300 other queries in their inbox.
If you're looking for query advice, but are slightly intimidated by my claws, blade, or just my rolling googly-eyes, check out the query critique boards over at AgentQueryConnect. This is where I got my start, with advice from people smarter than me. Don't be afraid to ask for help with the most critical first step of your writing journey - the query. My comments appear in green.
When Antheia's father is killed after an attack on a visiting princess, Antheia inherits his magical power. Only thing is, she never even knew he was a maege. And now that he's gone she has no idea how to use--or even control--his magic. Good hook. I'm drawn in. The only suggestion is have is a slight change in the wording on the first sentence. I had to re-read it twice because it almost sounds like he's the one who attacked the visiting princess. It could just be me, but I'd reconsider a slight rewording.
Her enemies are everywhere: agents who enforce the empire's proscriptions against maeges; the woman who killed her father and claimed to be his sister; and the brother of the princess who was assassinated. Antheia's lack of control over her magic makes her more dangerous to herself than to others. Pursued by both allies and enemies, she needs to obtain three things: access to a teacher; information about her parentage; and revenge. Her loyalties become dangerously tangled when she begins to suspect that her father lied to her about everything. This is all good and well written and does a great job of showing us the danger and adventure in he story, but we know nothing of what our MC is doing on a daily basis here. If her father was killed in an attack on a princess, I have a feeling of court life... but that he could have been in court because he's the cook. I don't know if he was a king or a jester, or what her position is in life on a daily basis aside from being a maege.
When she finally learns the truth about her heritage, Antheia must choose between the conflicting demands of blood-ties and friendship. I definitely need to know more about the conflict here. Friendship to who? Is it the princess? You haven't mentioned any other characters and she sounds ver isolated. She must rethink everything she thought she knew about her father. And most importantly, she must decide what she will do with the power she inherited. The world is changing around her, and she will have to choose a side. But first, she must learn who she truly is, and what she might become if she makes the wrong choice. Good -well written, and we know what the main thrust of the story is. The problem here is that we have no concept of the day to day life of our MC, or even much of a grasp on her personality. Is she happy? Sad? Good? Bad? Wicked? The only thing I know about her right now is that she's conflicted - and that's great. But we need a more human angle on this to be really sucked in.
My short story "Changeling" recently appeared in the anthology The Modern Fae's Guide to Surviving Humanity. I attended Clarion West Writers Workshop in 1997. Good mention on the first bit, I'd scrap the second as it was so long ago as to not be relevant anymore.
LIKE BREATHING is a 122,000-word fantasy. As per the current submission guidelines, I have posted (whatever the guidelines request) below. Thank you for your time and consideration. You don't have an age range indicator on this. Is it YA? The presence of a father makes me think yes, but the MC could be in her 20s for all I know. Make that clear either in the query by stating her age or calling it YA here (if it is). Also your word count might be a tad on the high side. Yes, fantasy gets wiggle room for world building, but even so it's smarter to try to keep it under 100k for a debut searching for representation.