I'll offer an example to follow, but you'll want to work on your own essay.
African Americans
One specific challenge:
Even after being granted citizenship and voting rights after the Civil War, African Americans still faced discriminatory practices in voting. Poll taxes, literacy tests, and other means were used to block black citizens from exercising the right to vote.
A method used to overcome these challenges:
The civil rights movement (with leaders like Martin Luther King, Jr., Malcolm X, and others) worked to end Jim Crow laws and other forms of discrimination against black citizens. Sit-ins, marches, and other means of protest were used in the civil rights movement.
24th Amendment, outlawing poll taxes (one of the ways poor black persons were kept from voting)
The Civil Rights Act of 1964 prohibited unequal application of voter registration requirements, as well as protecting against racial discrimination in other matters.