Technical answer: there is a preview system on Wordpress blogs, but I'd need to figure out a good way for you to peek at the preview.
I guess one key to success in blogging is feeling confident that what you write will be interesting to people. For example: I tend to believe that everything I say is fascinating. This perhaps unjustified belief gives me enough confidence to talk endlessly about a wide variety of subjects, and over the years some people have started listening to me, which reinforces my confidence.
You may lack this key to success - or maybe I just chose the wrong list of topics. If there are other topics you feel you have something interesting to say about, try one of those!