Hey... good decision to make a blog and start.
Well, the advice I can give to you is to try to stick to the theme, depending what your theme is.
If you plan to write about dogs, then don't write 100 dog articles and 5 cats, and 3 hamsters... stick to dogs then. However if you want to write about domestic animals than you can write about most of them.
If you have something like psychology or social environment blog, than you can cover wide range of topics.
My advice is to start with very precise themes. For example in Internet marketing industry the most successful blogs are those who are concentrating on one segment of the theme... Like social media (sometimes only facebook or twitter or instagram) or SEO or whatever... I hope you get my point.
I know it might sound confusing, but thats best I can offer based on your question...
Just dont make blog that deals with all sorts of things from making money online to how to get a date... find your theme, find your audience, and find your role models, and stick to them, eventually you'll evolve and understand how they talk to each other and how to get to them...
For wordpress my advice is dont get all those shiny features and themes with 1000 options... keep it light and fast and concentrate on value you provide to end user