When preparing for Presidents competition, divide the presidents in the range for the tournament among your players. Have each player gather information about the president(s) assigned to him or her. Give each player a list of the information they must amass, such as: childhood family life, education, political offices before the presidency, major domestic events of presidency, major foreign events, life after presidency, etc. You could do one of the presidents and present a handout of the information as a sample to follow.
Give players suitable advanced notice before the first Presidents practice. Then at practice, have each player hand out the page(s) of information compiled on each president covered in that practice. As a follow up for that practice or later practices, have each player submit one or more questions in 6-4-2 clue format about each president the player researched. (You could give students sample questions as guidelines.) Use their questions for practice as the supply lasts.
With this approach, each player will learn more about the president(s) he/she researches. Also, the other players will pay more attention to the information distributed because it comes from fellow students.