There was a lot of information on the do's and don't of blogging.  I am going to list three Do's and three Don'ts, that I felt were the most important

DO's

1. Have a contact link on you blog and make it visible.
2. Look at the readers point of view, are you addressing the audience in a way it makes sense. 
3. Make navigating you site clear and obvious.

DON'Ts

1. Don't write long posts, they are more difficult to follow, and reader may loose attention.
2. Don't copy more than small portions of someone else site, make sure to give credit to them.
3. Don't make you header to tall, so you readers have to scroll to see your posts.