1. Be clear about the central argument of the article.
This will be much more focused than the larger questions driving your thesis and should showcase your original contribution to knowledge.
2. Treat the article as a separate work.
It is highly unlikely that any given chunk of your thesis will be automatically publishable. You will have to rewrite your chosen thesis section to craft a submission-ready article that foregrounds your more focused central argument.
3. Sell reviewers on your original contribution.
This comes from having a clear introduction and a secure and well-evidenced argument that carries through the core of the article with appropriate signposting.
4. Respect the conventions of the genre.
Article writing is different from thesis writing. It requires you to be concise and specific. Ensure your language and register are suited to the task.
5. Research the journal you would like to submit to.
What type of articles do they publish? What are their style and referencing guidelines? Does your article seem like a good fit?
6. Proofread your work and/or enlist a friend or service to do so for you.
The odd missed typo can happen but a manuscript riddled with errors will likely be passed over.
7. Take any requested revisions seriously.
If asked to make revisions, make an earnest effort to enact sensible suggestions from reviewers. In the case of conflicting or poor feedback, seek advice from a supervisor or colleague or contact the editor for clarification.