I know this thread is about starting a crypto blog, but let me give you the real deal... Unless you're a SEO wizard, there's just too many cryptocurrency blogs right now. So many websites, so many review websites, so many news blog. And this scene is so new that everyone that can do 1+1 is skeptical about a new, unknown blog that is trying to say "hey! please buy this coin that I'm invested in!"
So if you really wanna try your hand at making a crypto blog, rest assured that you will have to work harder than everyone else. Other than that, you can focus on creating tools. Currency converters, mining profitability calculator, etc. Or make local content in your local language (English is really too saturated right now).