What are two ways Southern states went around the Fifteenth Amendment?

Two ways southern states went around the 15th Amendment were setting standards like being able to read (literacy tests) and a poll tax. The reason why being able to read was a standard is because many of the enslaved were refused to learn how to read and write in fear that they might run away. If you can read, then you can read a map. The poll tax was a standard because if a man had a father or grandfather voted before the abolition of slavery then one wouldn't have to pay for the poll tax. Of course this meant black men wouldn't be able to vote without paying a tax, and many were less fortunate so they didn't have the money to.