Laura at OnlyMarketingJobs is a great writer (and a fabulous person). Her advice in this blog post is spot on - when you are creating content write like you're having a chat.
The famous British Broadcaster Terry Wogan said about broadcasting on the radio that he only ever talked like he was having a conversation with one person - and that is true of writing blogs.
Imagine you are just having a chat with someone who is interested in your niche in business and write like are having a chat. All that needs to be added is a little courage to believe in yourself!