Great tips, Susie! I particularly recommend not rushing to publish too soon. One way I stop myself from doing that is to not write directly onto Medium. I like to write and edit elsewhere and then copy and paste to Medium once I'm happy with it. Up until recently, I was using LibreOffice Writer, but I have now started using Google Docs instead.
I also like to use Google Keep for saving ideas. This is because I can access it both via the app on my phone and through a web browser on my computer. Any time I think of an idea for a possible article, I save in there. I also often make brief notes of what I might write about. Not necessarily a full article plan. Sometimes just a few lines to indicate what bits I might cover in the article.