Content is the king - In the blogging world so diverse and big, you need to establish yourself with a distinction. the only road to it is good, original and valuable content. Be creative, different and surprise your readers once in a while.
Grammar - Depending on the language you use, blogging just makes it imperative that you are reasonably good with your grammar skills and proficiency if not a master. Remember your audience is a mix of both; the ones who are experts and the ones who are not.
Focus on good content, not on monetization. Over time, money and benefits will follow good content.
It was lovely knowing your takeaways from 2017. Now, let us hear your wishes for 2018. Aren't we all looking at the new year with love and hope? It is better to write down and then refer to it regularly if you really care about them.