You have plenty of ideas about what you want to write, how much you plan to write each day, and other tasks that will further your writing career. But how often does the day slip away? All of your good intentions to write are easily erased by other things that pop up in your day, both important and trivial. This is why you need to set goals. And not only set them, but write them down where you'll see them. That way they'll seem official to your mind, something not to be missed or ignored.
Personally, I write down my goals in a notebook that I keep by my desk. That way when I see it, I know I have writing to do. And inside, I've written down exactly what that writing entails. I have my weekly time goal (which, at the moment, is 25 hours dedicated to writing type stuff), my daily word goal (which is 500 words, though that usually turns into over 1000), a reminder of which blog posts I want to publish that week, a reminder to read at least a chapter in a book each day, and a reminder to publish something fun on my Facebook author page each day, and other such things. You can see not all of these are pure writing, but marketing of sorts, too. In my 25 weekly hours, for example, I allow myself to count my time on Twitter provided I'm clicking on links, commenting on posts or links when I have something to add to the discussion, retweeting, and generally marketing myself as a writer. Since using social media is a part of being a writer nowadays, I have no problem counting this time as part of my weekly hours.
As you can see, goals don't have to be overly specific - I don't break down how I spend each of those 25 hours, and as long as I'm writing some type of fiction, be it a full piece of flash fiction or a part of a longer story, I don't worry about tracking those words. I also called some of my goals reminders. Anything to make the writing day and week productive. Try it yourself. Start small so you simply get in the routine of not only setting goals, but following through on them.
And speaking of following through on goals, the best way to keep yourself honest is to offer yourself a small reward if you complete them. Pick something that will motivate you. Personally, if I finish all of my goals (note I said all - if I get my 25 hours, but haven't finished my words, I didn't earn my reward), I download an episode of a television show on Amazon. I've been doing this for a month, and so far I've earned the first three episodes from Season One of Star Wars: The Clone Wars. For me, I figure I can afford to spend $1.99 for a week of completing all of my writing goals. You may do something like this, or you might choose to allow yourself to watch a completely frivolous movie on Netflix or DVD or whatnot. You may treat yourself to a movie in the theater, a new book download, a decadent cupcake from a local bakery, or whatever else you can think of. As long as it motivates you to complete your daily, weekly, or monthly goals.
Set goals. It'll help you accomplish more. And reward yourself, even if it's just something small. But don't cheat, either on your goals or your rewards. The main point is to become a better author. So good luck, and get started!