You will need a proper command of English, without making grammar errors or typing typos. However, publishing in an online magazine or in your own blog is not akin to taking part in a literary competition, so you don't need to be a Charles Dickens or an Oscar Wilde to cut the mustard. For instance, my mother tongue is not English, however I reckon that my articles are written well-enough to be understood. Also, your way of expressing your ideas in writing needs to be coherent, or otherwise readers may not understand what you intend to convey. So before you submit your proposal, you can ask your colleagues or friends to read a sample of your write-up, ask them what they understand from it, and make sure it's the same as was intended.
Writing is a commitment which requires time and energy. In my case, considering all the time spent all throughout the process (jotting down ideas, writing the article, editing it, incorporating feedback, reviewing it many times, and several others), an article for Smashing Magazine takes around 5 full days of work on average, plus the research time, which could take a few days or, in some cases, even weeks.
So being able to manage your time adequately is a must. As a starter, choose a topic that you can persevere writing about, and which will not get out of hand (for instance, had I chosen to add 1 or 2 extra CMSs to my Smashing article comparing WordPress and October CMS, I would've been unable to cope with it). Additionally, you can consider asking your employer for time off work, and devote that time to write your article. After all, mentioning the name of your company in your article (even if only on the author's description) may already make it worth it.
Ability to identify important issues and explain them clearly permalink
Different factors are in play for deciding if an article is valuable, such as its amount of creativity, the depth of its research, the degree of technical knowledge involved, the newsworthiness of the concerned topic and the size and composition of the target group who will benefit from reading it, among many others. From the universe of all possible factors, I believe that the most important one is the clarity of explanation.
I will elaborate by showcasing a piece submitted to Smashing Magazine: article Understanding And Using REST APIs, which focuses on the REST API. Taking into account that this article was published in January 2018, that the concept of the REST API was invented already in 2000 and popularized in 2006 (when Twitter made available its REST API), and that REST had its apogee and is nowadays possibly in decline (with GraphQL claiming its place), I would have expected that, by year 2018, everything would be said about it. Yet, this piece has, to date, received 122 comments, making it an extremely popular article. How did this happen?
Reading the article, it is evident that its popularity arises from its clarity of explanation of the concepts involved. The author does not assume at any moment that the reader knows what a REST API is or how to use it (or any amount of technical knowledge), but explains these in very detailed steps and providing plenty of examples. Through the comments, many readers expressed their satisfaction about the article's comprehensibility:
Thank you, that was the most simple guide I ever came across. I bet will help loads of beginners.
Very nice, simple and comprehensive article on REST. thumbs up
Thanks very much for this! Its so concise extremely helpful for those of us just starting. Keep doing what you do!
Excellent article, Zell. Thanks for the efforts to make one simple to read and comprehensive.
Awesome! Great article and easy to understand. Thanks Zell!
This article evidences that, even if a technology is old, new content can still be created about it if it satisfies the needs of the people who must use the technology. And the most important need is: people must understand it. Hence, the more concise and comprehensible the write-up, the more valuable it becomes.