There's definitely an art to writing an interesting and engaging blog. I've been blogging for almost 4 years now and I'm still trying to find my way in terms what to write about that would be of interest to you.
Sometimes I go off topic, but for the most part I try to keep the subject of Monday posts writing related whether it's a piece on research, my experiences doing hands on research, the mechanics of writing, promotion, or just writing in general.
My Wednesday posts have changed a few times. I was doing book reviews but wasn't always able to read a complete book and put together a review in time for the next Wednesday post. I started posting items and links to articles I found interesting. I've modified it a bit to include how my writing has gone the previous week, a random item that occurred or item that popped in my head during the week. I kept the motivational quote that I was posting before because I find them to be inspiring and hope you do too. The hardest part of the Wednesday post is the random photo of the week. I'm not a person who takes pictures on a regular basis. Even when I go on vacation, the last thing I think about is "I should be taking a photo of this." Sometimes coming up with a photo to post is harder than I thought it would be. I also still host guests on Wednesdays when I'm asked.
The "This I know for sure" posts on Fridays are my favorite to do. It could be because the subject of the posts can be about anything or nothing in particular at all.
When you visit a blog, what keeps you coming back or subscribing to have the post sent to your email? I'm always looking for ways to change my blog and keep it interesting so I'd love to hear your thoughts.