Narrow down your list to about 3-5 applicants.

Once you narrow down your preferred markets for purchase, hire a knowledgeable realtor who understands the STR regulations and the "sweet spot" of each market. 

Have you narrowed down the type or area you want to invest in?

Once you have those narrowed down, get a good realistic understanding of what it will take to be successful in that path.

My recommendation is to narrow down to the top couple areas you are interest in, maybe create a relationship with a realtor there, and then just go on Airbnb/VBRO like you are about to rent a house there - that will at least get you ideas on what you can expect a similar property to rent for.  

I live in NJ and looking to purchase my first STR, I am just really having a tough time narrowing down a specific area on where to buy.

Lots of options in So Cal for these types of investments, I would say the first thing you want to do is to start narrowing down what type of investment you want to make first and how much time you want to allocate to your investments.

The first step in my opinion is to narrow down your buying criteria and area.

In a narrow chimney a liner can be difficult.  

I've got a list of vendors to call today and am hoping to have this narrowed down soon.