This is great post by Darren Rowse of Problogger. He explains why the first impression of your blog is so important. The subject 'first impression' is crucial, because this is going to influence your relationship with one and other for the time to come. This goes for when you going to a job interview, the employer will take a closely look at how you dressed, your body language and the tone you are communicating before he is hiring you.
Darren explains how you should impress your first time visitors. He is talking about that you should consider the tone you are writing in. The post's title should attract your visitors to read the first line of your post. And the first line got to be catchy enough to invite the visitor to read the whole post.
I think if you want to readers to return you got to be aware as a blogger how your template looks like. Does the color of your template leave a hot or a cold impression? This will attract certain kind of visitors and will be rejected by others. I think Darren explains it all in 7 minutes.