The problem is IMO that you may not understand all of the risks if you don't visit a property in person.

Went to visit a builder in Frisco on Monday afternoon. 

@Eric Dame It's best to visit a few surrounding parks.

The best advice that I got but didn't listen to when we bought our duplex, was to visit A LOT of properties and take A LOT of time to make sure you are getting good deal.

Take the time (or have your Realtor) to actually visit a crappy looking property to see what the deal is. 

I am going to visit a friend in Portland next month, and I thought that I would like to check out some investment opportunities while I am there.

Many tend to visit a few different beaches before choosing their favorite.

Trust your gut and personally go visit a job he's doing to see his work.

By that I mean you should visit a couple single family and multifamily open houses to see what you personally prefer. 

The game is to hope that the taxpayer does not pay off the next quarter tax bill, and you get priority to pay it off and receive 18% interest on the next one... but again, you have to have the money in the bank to pay off each property tax bill thereafter or lose priority.My advice is that if you are interested in tax liens is to visit a couple of tax lien sales (if you don't want to pay for a database access, then you can always go to each municipalities webpage and see if they list the info there), and see how they operate.