How do you build up a good online reputation for yourself as a writer?

First o all, you need blogger ethics, always write reference and link, even credits to the original post if it was news for entertainment, or any type,don't steal others posts, don't mimick others ideas, keep your ethics high to be respected and have good reputation.

1. I write quality articles and blogs and make sure they are credible.

2. When optimizing, I use only white-hat SEO.  I never attempt to use black hat, which is easier and quicker to get results, because it can only ruin my reputation.  

3.  When I do blog commenting, I make sure that my comments are relevant to the topic; and I comment sincerely.

4. I don't plagiarize.  I simply hate it. 

Now i don't doing any thing because i dont have time to do that ... but if i want to do that i will open blog for news and more which i can put my writing on and using new media to give more view ...