In the online world, content is king, but your keywords are what will get you and your site found. While you certainly don’t want to keyword stuff your blog posts, you do want to use keywords with reasoned forethought and for a purpose.
How can you determine what keywords to use? Here are some tips.
Think like your customer.
How would your customer search for you if he or she went to Google? Not sure. Ask them how they found you. If they typed in, “pool service company in Michigan” or “best pool contractor in Florida” you might want to consider using those keywords as they are what your customers are using. If you get too clever with your keywords or key phrases and your customers never use them, you’re potentially losing customers. While you may be the “dog groomer to the stars” your customers may be searching, “dog groomer in Brooklyn” and if that’s what they’re searching, that is what you should be using. 
Know what customers you want to target.
Remember you can’t be all things to all people so choose keywords based on the clients you want to target. You may want to use different keywords at different times of the year. Pool keywords in the summer months, hot tub key words in the winter, for example. If you’re looking for new clients for your “upscale hair salon” then begin using those words. Again, the keywords or phrases must be something your client would actually use.
Don’t keyword stuff.
The SEO by Yoast plug in for WordPress shows you, visually, how many times you’ve used a particular keyword or phrase and you may need to use more or fewer in order to get good SEO rankings in the Yoast plug in. There are other ways to determine keyword density, but this is a helpful plug in.
Do a Google search for your potential keywords.
If you’re not certain who else might be using the keywords you’re considering, do a Google search. Is that phrase being used everywhere… or nowhere? That could be telling and could require more research on your part to determine whether it’s a word or phrase worth capturing. Look at your Google analytics and take a deep dive to see what people are using to find your site.