You should start looking at properties and learning property values in the areas that you are interested in.
I love Zillow and Redfin! I use those apps every day! I think they are a good place to start. They can help you learn property values. I NEVER look at Zestimates! I spend a lot of time looking at properties that are for sale and properties that have sold. I'm looking for a duplex in Georgia. I've seen fixer-uppers and turn keys on there. It has taught me a lot about property values in the areas I focus on.
People can list a property for sale for any price they want. It's the SOLD prices that I pay more attention to when using Zillow or Redfin. That's the same way a realtor would pull comps for a property, by looking at other similar SOLD properties. I see some multi-families sit for sale for a long time. I assume they are priced too high or they need a lot of repairs.
You can set up Redfin to email you when properties are listed for sale, pending, or sold in different areas that you choose. It can help you learn your target area without having to search the apps or websites everyday.
First, pick a search area. It can be a state, county, zip code, etc. Where do you want to invest? For me, it is the county I live in and the 4 or 5 surrounding counties. Next, what kind of property are you looking for? Single family, multifamily, vacant land? For me it's multifamily. Set up all the details you want. I get emails almost every day for properties in my search areas that are listed, changed to pending, or sold. Every time I see a new listing, I will analyze it to practice. I'm looking for cashflow. If I find one that I can afford, and that will cash flow good, I will make an offer on it.