In order to write well:
1. Read actively.
Depending on your schedule, set a goal. It may be one novel a week, whatever you can handle.
Try to read the 100 books that are most similar to what you write. For me, I began reading historical fiction focusing on the late Roman Empire and early Medieval Ages. Then I began reading about the Greeks, Vikings, and Crusades. This helps you find your niche (how your book is unique) as well as what people expect from your genre.
But don’t get stuck on your genre. I’ve enjoyed reading Harry Potter, Pendragon, Hunger Games and books about modern warfare. As you read, pay attention to characters that you like (or hate). What can you use from the battles, scenic descriptions, dialogues?
If you don’t have time to read, get audio books. I listen to these on my commute, while I wash dishes, and as I fall asleep.
2. Write consistently.
Again, set a goal. 1,000 words per day seems like a noble goal for me. It takes me one or two hours and keeps me on track to finish my novels.
I wish I were one of the writers who could just start a story, write it, and end up at the end, staying excited about the book because I don’t know where it will go. But for me, I need an outline, and I keep jumping around it until I finally finish — some place in the middle.
As you write, keep track of things you’ll need to change. But keep going! It’s more important to finish a rough draft than to make a good rough draft. Here’s why: if you finish, you can go back and fix it because you now know how your story goes. But if you want a good rough draft, you will probably never complete it.
3. Test regularly.
It’s great if you love your book. It’s better if others love it, too.
Share it with friends and family. (Especially if they can give you more input than just “Good job.”) During this time, don’t even look at it. This way you can later read it fresh.
You need to know that your book is the best you can make it, so that you don’t give up when rejection letters arrive.
When it’s ready, sent it to competitions, agents, publishers.
In sum: set goals, stay consistent, and enjoy meeting your characters and building your world!