I'll say this first, all stories written are just previous stories with the writer's own twists. Everything's been done before, but that doesn't mean you can't use one or a few of those ideas. Just add your own touch to them. Of course, unless you're writing a crackfic to post for whatever reason on the Internet, don't shove everything your pretty little brain can think of into your novel. It has to make sense, or at least seem like it makes sense.
Your readers aren't idiots. They don't need you to write paragraphs after paragraphs explaining every little thing. Some things are better left shrouded in mystery, piquing the reader's interest, others are better off explained in a few short sentences. Once you explain something, you don't need to repeat it every chapter. Stay on track. Don't start recapping the events like you're some commentator. It gets annoying.
If there are no emotions in a novel, it makes the novel feel like a manual or a textbook. Boring. If you want your readers to laugh and cry along with your characters, describe their emotions. Put yourself in your characters shoes. Even if you haven't experienced what they're going through, think about how they would be feeling.
Here's a body language cheat sheet to help you: [link]
There's absolutely no conflict in your story. People read stories to live another life through the characters. If they can't relate to them, they won't experience their life. The characters need to want something and that something needs to be worthwhile. There needs to be setbacks, things that prevent the character from getting what he or she wants. Make the reader want to stay and root for the characters.
The readers don't have to love your character, but they have to care about what happens to them. If they don't care about the character, they don't care about the book.
Antagonists don't have to be pure evil, the same way protagonists don't have to always be good. The antagonist may have the right goal in mind, but they're going about it the wrong way. The protagonist might resort to underhanded tactics to get what he or she wants. That's okay.
It might be a little hard to tell when you should begin your story. Just write enough to make your readers care about what happens to the character and make them continue reading. If you jump right into the action, say your character about to be killed by a monster, why should the reader care about their death? They don't really know much about him or her. Back up a little and try to express that character's motivation. You don't necessarily have to tell the reader what the character wants, but they should know that the character wants it.
Lazy writing is bad writing. Laziness isn't just limited to letting the draft sit there unedited for weeks, months, even years. It includes relying on cliches and telling instead of showing what the character is feeling, thinking and doing. Don't keep your readers away and give them a detached summary of what's going on in your head, show them.
Writing a novel is a lot of work. Sometimes, you just sit there for hours, staring at a blank page, waiting for words to come to you. At other times, you might be staring at a draft wondering how you're supposed to improve it. If you don't write your novel, then who will? It's certainly not going to write itself. You have to write it. It's your story, isn't it?
I hope this helps and have fun writing!