Determining an ARV on a property

[Ellis Fairley]

Hello Bigger Pockets! I'm somewhat new to the investor world and eager to learn as much as possible. My question is, what are some ways you guys determine an ARV on a property? I'm aware of using realtor sites like Zillow and Trulia to make comps, but wanted to see if there were any other ways. I know that these sites aren't a 100% but a rough estimation. I've also heard of looking up the tax appraisal but I'm not too sure on how to calculate the data from it. Any help would be greatly appreciated! Thank you in advance!