That's right, the keywords they are looking for will be looked for in the titles. In other words, if someone types "Etsy marketing tips" into a search engine, that search engine will look for those words in the titles first. So if you have those words in any of your blog post titles, your blog is more likely to come up in the results.
This is a great tip to remember when naming your posts. Even though you might want to call your post "So I was thinking..." or "Big idea of the week" those titles aren't going to help you get new readers. If your post is about Etsy marketing tips, you need to get those words into the title somewhere. A good way to decide what to title your posts is to ask yourself "if I was searching for this information on Google, what would I type into the search engine??"