My advice is write all the time. Get used to the process. Your third book will be better than your first, so get going, and start the learning process. And don’t worry about having all the answers before you start! No one does. Those usually come to you as you write. I would also suggest that you read widely, too, and think about what you like and don’t like in each book. It’s a great way to learn.
THANKS FOR PRE-ORDERING #NEMESIS! Pre-orders really help an author get momentum for a book project.