Lately I've been doing a lot of manuscript and query critiquing, and I'd like to talk about a writing issue I've noticed. One that can possibly help with your query as well as your manuscript.
No base plot thread. No main point. Basically, what is the main character hoping to accomplish? Or what do they need to learn?
I'll use a few popular movies and books to explain.
ANNA DRESSED IN BLOOD by Kendare Blake: In the first chapter you meet Cas, a ghost hunter, and you see that his goal is to find a ghost named Anna and kill her.
How to Train Your Dragon (movie): Early on you see that Hiccup is not like the other vikings. He wants to be accepted and loved by his dad, which means he needs to learn how to deal with dragons, one way or another.
TWILIGHT by Stephenie Meyer: In the first chapter Bella is new to town, and not too happy about her move. She sees Edward and is intrigued; she wants to get to know him, see him again.
FIRST GRAVE on the RIGHT by Darynda Jones: In the first chapter the main character, Charley, is approached by the ghost of a dead guy asking for her help to find out who murdered him. Also, a very old undead being contacts her and whispers a name no-one should know, other than her.
From the get go, the reader/viewer has an idea of what to root for. It's as though the writer has left bread crumbs on the plot trail, enough to keep the reader/viewer traipsing down the trail. Hopefully enough to make the reader want to run down that trail, full speed ahead because they just HAVE to know if the main character is successful. (Of course there's other factors in writing a can't-put-down story, but I'm focusing on this one.)
I see the main plot thread as the main color of a tapestry, woven through the center. You need it to keep the rest of the threads together, to make them mesh and the complimenting colors pop. The story opens, you show the inciting incident (what spurs the main character). Then at about 15% in (give or take) you have the first plot point (when the MC decides to venture out and change things up, while still sticking to the basic plot thread.)
For example, in How to Train Your Dragon a band of dragons attack the viking's village and Hiccup tries to help, to make his dad proud, but he screws up and ruins everything and in the process hurts a black dragon, Toothless. That's the inciting incident. When he meets Toothless and helps him, deciding there may be another way to save the village from dragons, that's the first plot point. All the while, he's still seeking acceptance from his dad and the villagers while trying to keep the village safe from future dragon attacks, which is the main plot thread.
Look at your manuscript. Does your main character have a goal/motivation? What is it? Why? This question should be answered (hinted to, at least) in the first couple chapters. It's what causes the reader to continue down that path, knowing which way it's headed and promises more bread crumbs. And it shows the reader what's so special about your story. What makes it unique.
So if you're having trouble creating a query, it could be because either you're not realizing and showcasing your main plot thread, or you don't have one.
Tell me in a couple sentences, what's your main plot thread?