ProcrastinationIf you're having trouble getting started writing your novel and you're reading this, then you're almost certainly guilty of procrastination. As soon as they're sat down in front of the computer, people will find all kinds of other things that could be gotten out of the way first - everything from laundry to watering the plants to checking the news to preparing dinner...
Yes, the blank page is a daunting thing, and the first few sentences are arguably the hardest, but at some point you've got to sit down and write some words. Or stop pretending you're going to write a novel. I know it's harsh, but it's only because I care about you.
Fear of FailureSome people sub-consciously (or consciously) put off getting started because they're afraid of failure. What if they're no good? What if their friends and family laugh at their poor attempts? Well, I'll let you in on a secret. Your first novel? It's not going to be any good. Your first novel is a learning experience - it's not going to be your masterwork. And unless you have spectacularly bad taste in friends and family, nobody is going to be that mean. In anycase, if you're worried about that, don't show them. Personally I don't think sharing work with friends and family is particularly useful anyway, but that's another post.
Finding the TimeThis is very closely linked with procrastination. A lot of us are very busy, with full time work or study, chores and other hobbies. So it can feel like it's impossible to find enough time to write a novel. And writing a novel takes a long time. But as the old saying goes, 'If you want something badly enough, you'll make time'.
Even if it's just half an hour a day, that's enough to make progress. Think about how much time you spend on leisure activities such as watching TV or playing computer games - can you shave half an hour off there? Could a parent or friend take over childcare duty for a few hours a week to give you a little time to write?
Once you get over these problems, which are completely unrelated to writing and completely related to character and attitude, you'll be ready to start writing your novel.