You have doubts if blog is for you and if it is a useful tool. There are some ways to check it and find answers. Before you start to work on your blog seriously, before you spend money on it, before you invest your time, check if it is really for you.
I work as a PR specialist with people who are experts and who have been building their position in different markets. We work together on building a bridge which reaches their goals. Both my experience and my belief let me create 7 rules which are features of a good PR specialist to my mind.