To write better you will also need to read better and to train much more. Read my article to get some basic ideas about how to get better writing skills.
Before we start writing we need to start reading. How do we do that. Wubscribe to all the blgso you can about the subjects you want. After two weeks of intensive reading your brain will already have more than enough information to start the writing tasks.
Open an account on Squidoo to start your practice. I recommend Squidoo not because of the money you will make, but because of the detailed stats about all your pages. Squidoo just so happen to be the best place to keep track of the performance of your articles on search engines, on sales, traffic sources and so on.
Of course you can always buy your own domain and take things to the next level but this is too complex for the average internet surfer and it takes too long and costs money. You will not be able to get that money with in the beginning with advertising programs.
Now start writing about any subject you want. I recommend you to write more than 10K characters about the subject you want, because on Squidoo the more content you have, the better you will score on search engines and on Squidoo itself.
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10K will take you about half an hour, maybe more if you are a slow writer. After all that writing hit the Publish button and wait a few days to see the results.
Write all the lenses you can, about many subjects. Do not stick with computers all the time or cars all the time.
Writing about subjects you know nothing about is the greatest exercise of all because you will force your brain to work in a higher gear. Your improvement in this case will be the best, with no side effects.
Once you do it naturally you can then write for other sites like Triond, or you can get your own domain and write for yourself.
Just keep writing that the skill will come out naturally.