I think having an official thread for sharing blog posts with advice is a good way to keep things organized, so I'll be closing all threads with blog links and forwarding them here.
*Note* I am selling my new GIMP for Beginners book (which comes with access to premium videos) on this website. But you don't have to buy, or sign up for anything to get the free GIMP tutorials and videos :)
I wrote the post because I was finding it so hard to connect with other sellers online. You'd be amazed how many people aren't paying attention to these things.