There are two types of writing- personal and public. Personal writing would count as the journal on you desk or the writing you never let anyone read. Public writing would be published novels, newspaper articles, your English essay you should currently be writing, basically, anything you read that is not written by you.
If you are constantly writing personal writing, you are writing for yourself and only yourself. The only feedback you have to go on is the feedback you give yourself. That my friends can be a very bad thing indeed. You are one in seven billion. I am sorry to tell you this, but not everyone thinks like you and is entertained by the things that amuse you.
So, now is the time to stop writing for yourself and start writing for others. think about what they might like instead of what you might like. But, be sure to include things that you like. After all, this is your book and you should to love it. People want to hear what you have to say. They just don't want to be bored to death while reading it.
Let's say you do try to start writing for others. You pick up a pen or open a word document and start putting down the first words of what could be your best work yet. Everything is going fine until you realize, hey, I suck at this. A lot. Public writing won't come easy right away. Granted, there are a few talented people who might pick it up right away. You have heard it before, but I will tell you again. The only way to get better is to keep writing. Write, write, write!