Bloggers are writers. Even if you're into photography, video making or sketching and drawing.. and are blogging about those skills, you need to write well.
The more you share your posts on social media & the more you engage & entertain your readers, the quicker your readership will grow.
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.
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.