Here are some quick general tips for effective writing that I have picked up over 5+ years of science writing on the web.
Deciding a topic
Your article adds value if it:
a) Provides new information to the target audience on the selected topic OR
b) Presents existing information in a contextual way, so that people gain added perspective on the matter.
Do not think people are not interested in a topic, or it has already been covered many times. People are interested. And if you use the thumb rule above, it will ensure that your article is unique.
Do not add any images in the first draft of your article. The content should be readable and palpable all by itself. Images add value, and you can put them at the end, but they aren’t a replacement of the content itself.
Where to publish?
Always dual publish. One copy goes on the platform where your audience is (Medium, a publication, etc.) and the original anywhere else you can. For the latter, I suggest a solution that you control, like setting up your own website/blog.
Publishing platforms can go out of business anytime, sometimes even without due notice. They can change their policies in ways that may limit you arbitrarily. Many a times, it is possible that exporting your content from a platform to anywhere else isn’t aptly supported.
I cannot stress this point enough, own your content. Besides, having your own site ensures that all of your content in accessible in one place. Makes for a great CV.
Article published under the freedom-respecting Creative Commons Attribution-ShareAlike 4.0, minus any media file(s) credited independently.