Whether you are writing for the web or writing for a magazine, you need to have focus. In his book called The Dip, the great Seth Godin used the woodpecker to illustrate the points and ideas in his book. The same can be used to show the importance of focus if you are a freelance writer. A woodpecker makes its home in a tree by boring a hole through it. If it flies from tree to tree starting to make a hole then abandoning it to try to make another hole in a different tree, it will never accomplish anything. But if it focuses its attention in one tree then keeps at it, the hole and home will be finished in just a matter of time.
It is pretty much the same with freelance writing. If you jump from project to project, you will never end up with anything done at the end of the day. But if you focus your attention on one project and actually finish it before you start working on another one, the day ends with a finished project that you can mail to your client the very next day.
Time management is probably among the worst problems that freelance writers have to face everyday. But it can be less of a problem if you have focus. Do not take too many projects that fall on the same deadlines. You need to learn to say no to some projects when you see that your workload is piling up. Do not be too hard on yourself.
Focus on the projects whose deadlines are nearing. Get them done. Get them polished. Then work your way to the other projects.
If you are writing exclusively for the web, getting yourself to focus is even harder. With the availability of too much information and resources on the web, it's almost impossible to concentrate. There are things you can do though to minimize those distractions. Let's assume that you are looking for writing jobs online. The truth is that there are hundreds of job boards on the internet. Many writers commit the mistake of trying to use all of them. They think that if they try them all, they will accomplish more. Huge mistake. They in fact accomplish less because of the precious hours they spend navigating around multiple sites.
Don't commit the same mistakes. What you should do is focus your attention on 3 to 5 job directory sites. Pick the ones you think are suitable to your experience and skills. You will accomplish more in less time if you follow this technique.
One last thing, do not apply to all writing jobs that you see in a job board. You will only get lost and confused if you do. Just pick those that looks interesting to you and work very hard on your reply message to the job post. Hundred of applicants are probably applying for the same job so you have got to make your message unique and interesting.