I'm a big advocate of Kathy Sierra's "minimum badass user" strategy. Basically, try to write as little about yourself and write what will be most useful to improve someone else's abilities. I'm not amazing at this (yet), but it's my main goal.
Identifying too closely with being a "writer" or "coder" or whatever can be detrimental to doing more meaningful work. That's because it's all about you. But really, it should be all about your users and how you are making their lives better.
The more you can focus on "What will help my reader be awesome?" instead of "What will I write?", the better your writing will be.
Nobody cares about how awesome I am (and they shouldn't!), but everyone cares about becoming more awesome themselves. Resist the temptation to focus on yourself and shift that focus to them and you'll automatically be better than 99% of writers out there.
If you spend a week learning something remarkable and then show others how to do it in only an hour, it's a huge win for them. By focusing on learning and then sharing what you learned in a succinct way, you are accelerating the progress of others. That, more than anything else, will make you a great writer. The metric should be how much more powerful your readers are after reading your writing.
(Naturally, I'm talking about a specific type of writing here, not fiction or historical writing, etc.)