The hard thing about writing is not coming up with ideas. At times, ideas are flying through my mind and I can't seem to get rid of them. It's not a lack of time. I have plenty of time. The hard part, I find, is motivation.
What motivates me to write? I'll tell you.
One of my great motivations is a blank piece of paper. Not a blank Word document. A blank piece of paper. For some reason, unknown to me, I just can't stand the sight of a blank piece of paper. So, I start to fill it up.
Sometimes, I start listing characteristics that I might want to use in a future character. Sometimes, I start writing a journal entry. Sometimes, I write poetry. And sometimes, I write down ideas that I might want to add to one of my current, or even future, projects.
Whatever it is, the page is soon filled, and I can go on with whatever I was doing before hand.
However, that isn't exactly writing. What it is, is planning. You're planning ahead to future things that you can do.
Now, you can open your writing program, whatever it may be, and take something from the paper, say your character list, and start developing that character further, giving the person an identity.
Your mind, now, is in writing mode, and you can pick a project and start working on it.
Another method of motivation is something I call a forced start. There are a couple different sites that I use when I want to force myself to start writing. What both of those sites do is give me the chance to write without allowing myself to be distracted. Once I start writing, I'm not allowed to stop, until I reach the predetermined word count that I set.
Likewise, you can do this by yourself, if you can have self control . Set a word count, and then don't allow yourself to stop for anything until you finish that word count. While you're at it, give yourself a time limit, that you have to stretch to make. That way, you'll be forcing yourself to keep writing, to be able to keep within the time limit.
Then, when this exercise is done, you've written a good amount of words, and your mind is, once again, in writing mode, meaning, you can continue on going without pushing yourself so hard.