Make sure to use correct grammar, punctuation and paragraphs. Every time someone talks, you start a new line.

Don't switch the point of views of someone constantly. In a normal fanfic this can be confusing and annoying, but it is especially important in an adventure novel. First person may be easier, because you only have to say what the character says, but don't jump from character to character. Just stick with one character. Personally, I prefer to write third person. The reader will get less confused and they can see everything from many characters' perspective.

And finally, good luck with your story :)

If you're a rookie writer, you're more inclined to write a Mary Sue and a Marty Stu, don't let this happen. Create relatable, quirky characters.

Secondly, adventure is very hard to write. Read some books that are in these categories. For example, The Hunger Games and Harry Potter. You'll notice a couple of things:
Description is very important here. Little details are always described and the reader knows nearly every inch of the surrounding. A reader will become lost and confused if you only describe the place as the action is taking place, and after that, they'll become repelled.

Concentrate on one character at a time! Don't jump between characters. If they are in the middle of a fight, say what is happening with each character one at a time. They should all tie in with each other. Otherwise, it'll become hard to follow. In the opening of the Hunger Games, Collins only tells us what is happening with certain characters. Take your pointers from her or someone similar.

Take your time with it. There doesn't have to be drama in the first chapter. Take your time to devolp your characters and your plot.
Let the readers see how the characters are growing throughout the whole fic.

“Show, don't tell.” My English teacher loves this phrase. For example, if one character is rejected by someone, you don't have to necessarily show the scene happening. You could just have someone saying that they were seen crying after the day they planned to tell them.

Also, you don't have to use direct speech as well. You can use indirect. If you have too many lines of people saying “X” and “Y”, feel free to use indirect. It's makes a nice change. An example would be, “I don't know,” said Lee Joon = Lee Joon protested that he knew nothing about the incident. It's not a great example, but you get what I mean ^^

Well first off, you're gonna have to know those difficult writer terms sooner or later. Do research. Read adventure books, watch adventure style movies. Usually there's lots of action and suspense. Make the characters real and believable bc that's the sure fire method to keeping people reading. Dumb characters are repulsive...

Leave each chapter at a cliffhanger.
And my personals:
Always use good grammar
Proofread many times.
Write either really good emotion, or really good action
Use a readable font and space paragraphs accordingly =_=
Learn how to correctly punctuate dialogue
Try not to copy a plot from a popular movie/book/fic
Plot twists are nice

Um. Remember that a story is propelled by its characters and not the plot. The reason books and movies are popular are because the emotion felt is relatable.


My opinions anyway.