1) Reduce your blog's loading time
Most people tend to get frustrated if your blog does not load in 10 seconds. So, getting your blog to load in around 3-5 seconds is a good tactic in maintaining visitor's moods. They will also be slightly more patient to view your longer blog posts. If you don't, people may navigate away from your blog before they even see anything! To reduce the loading time, you should take away unnecessary widgets. I see many blogs around that have useless widgets, which means they do not satisfy the visitors anyhow or do not have any particular use.
2) Write short, simple but meaningful content
Stop twisting the story and get to the points straight away! If readers get bored at the part where you are twisting the story, they have a high chance of leaving. Add the interesting bits and just some of the boring bits. Oh, and inject some good humor too!
3) Insert (relevant) images or videos
Pictures and videos are more lifelike than just words. Colors also help a lot in this case. It soothes the eye after reading a lot of words. Please do not spam images and videos, just enough to solve the reader's boredom. Imagine you're talking about chimpanzees and you show your daughter's picture. Either you're really stupid to put such irrelevant photos, or your daughter is a chimpanzee!
4) Be interactive with readers
To make readers feel satisfied and comfortable reading your blog, you have to interact with them. This makes them feel that your blog is more real, and you can actually hear what they are saying (in this case, typing). Good feedback from readers are also very helpful for both you and the readers, so please listen to your readers!!