The history of third parties is a very interesting study. Typically, their electoral success is minimal-to-none. However, some ideas of their platforms are often absorbed by the major parties. In essence, their legacies are found in some of the policies enacted by administrations of subsequent mainstream politicians.
The Populists were no different. The late 1800s represented their heyday. They achieved some success at the state levels through such legislation as Granger laws and by electing some governors. At the national level, Congress even seated members from their ranks. They were unable to achieve electoral success in the presidency, however. Their best chance in this realm came in 1896, when the Democrats nominated a champion of many Populist ideals in trumpet-voiced William Jennings Bryan. He, however, was defeated soundly by Ohio Republican William McKinley.
Stanford University has a wonderful department in their education school called Stanford History Education Group (SHEG). SHEG has produced a series of lesson plans, called Reading Like an Historian, that utilizes primary sources as the driving factor behind achieving student interaction with the past. These inquiry-based lessons are posted on their website.
Additional lessons from the Gilded Age are also posted on the Reading Like an Historian website.