Everyone has already told you to practice. Do that. But find someone you respect go give you critical feedback. This is key - we tend not to notice critical shortcomings that outsiders can spot. In fact they remain shortcomings in part because we are blind to them and so never realize there is something to improve.
Paul Graham's essay http://www.paulgraham.com/essay.html talks a lot about how he does essays. It is likely to be helpful if you want to write like he does. And if not, it is still interesting.
In a very different light, http://perl.plover.com/yak/presentation/ has a lot of useful information. Most of it is about presentations, but his suggestion of getting to the point and embellishing is very good. And it is wise to understand what he says about people's ability to pay attention. Long form writing can easily exceed normal human limitations. Presentations and writing are very different mediums, but both hit the same human limits.
And finally be aware that people are not simply "good at writing". There are many different forms of writing, and they are at most correlated skills. For example I became good at answering specific questions in ways that are likely to stimulate further thought due to answering many thousands of them on Perlmonks. However I would not be able to write a decent fiction book to save my life.
Paul Graham's essay http://www.paulgraham.com/essay.html talks a lot about how he does essays. It is likely to be helpful if you want to write like he does. And if not, it is still interesting.
In a very different light, http://perl.plover.com/yak/presentation/ has a lot of useful information. Most of it is about presentations, but his suggestion of getting to the point and embellishing is very good. And it is wise to understand what he says about people's ability to pay attention. Long form writing can easily exceed normal human limitations. Presentations and writing are very different mediums, but both hit the same human limits.
And finally be aware that people are not simply "good at writing". There are many different forms of writing, and they are at most correlated skills. For example I became good at answering specific questions in ways that are likely to stimulate further thought due to answering many thousands of them on Perlmonks. However I would not be able to write a decent fiction book to save my life.