When you click on the main page of Ecommerce Bytes, it can feel a little overwhelming because there's so much info available on the site. Within this larger site, there are two excellent blogs with active participation from readers (many of whom are very experienced with online selling).
First, there's the Auction Bytes blog (or "AB blog"). The blog's editor, Julia Wilkinson, is an experienced seller on eBay and other auction and online sales venues. Recent topics include a discussion of whether or not thrift stores charge too much, and tips for selling slow-moving inventory.
The other great blog is the Ecommerce Bytes blog (or "EB blog"). This blog covers a broader range of ecommerce topics and is edited by the site's editor and co-publisher, Ina Steiner.
It would take a long time to go into all of the resources available on Ecommerce Bytes. Here's just one: an eBay fee calculator that helps you figure out what amount of fees you'll pay eBay and PayPal when you sell a specific item.
The comments from other sellers on both the AB and EB blogs are insightful and interesting, and by clicking on the links to the sellers' websites (sometimes listed with their usernames in the comments), you get a nice perspective on some of the different ways sellers are marketing themselves online.