Check out the blockpass blog:
https://medium.com/@blockpassTo start with you want to identify the topic you are going to write about and what it will cover (also, what it won't cover if you have a tenancy to go off-topic). You also need to select the kind of style you're going for (usually based on the audience you expect) - formal, informal, humorous etc.
When you know what you want to write about, you need to do as much research as possible/reasonable for the article. Read a variety of resources: articles, forums, wikis, research papers, whitepapers, related subjects, expert opinions etc. Also, if you can talk to someone knowledgeable on the topic you can get a wealth on info that might not be found anywhere else.
When you're ready to actually write, you should get the structure sorted. Usually you'll want to start with an introduction to the problem/situation/event etc and finish with a conclusion that sums up everything and maybe poses questions for the reader to contemplate or has thoughts for the future.
In between, I find it helpful to write a few words/one sentence on the various paragraphs I plan to cover, then check that I've covered all the points I want to make, then change the order around until it fits.
Once you have the plan ready you can flesh out those initial words/sentences into full paragraphs but don't be afraid to change the order around more if it suits you.
Finally, try and find an interesting title that gives a general feel of what the article will cover.
When you've finished, proof read it and if you can, get someone else to review it.
Good luck!!!! 
