Two articles that Xinhua published detailed the selection process for the new leadership candidates who were voted on during the 19th National Congress. The article gave an indication that, throughout the selection process, Xi Jinping was directly involved in weeding out his opponents. According to the article, the selection process started in February 2016, when a candidate selection committee that Xi Jinping led was first formed. During the process, Xi provided specific guidelines and criteria to use in the candidate selection. The criteria included, as the top priority, that the candidate must “meet political criteria and establish a political standard; the candidate must align himself with the Central Administration and be clear and firm about his political position; he must be clean and free from corruption while fit to get the job done.” From July 2016 through June 2017, the committee set up 46 observation teams to visit 31 provinces, 124 agency central administration agencies, financial institutions, and state owned enterprises to interview potential candidates. The Central Military Commission also formed 10 teams to visit military departments and agencies to talk to potential candidates. In the past year and a half, the candidate selection committee met seven times while the Standing Committee of the Political Bureau met six times to receive updates on candidate selection from the observation team. From April to June of 2017, Xi Jinping personally sat down with 57 existing party leaders to hear their opinions. The Political Bureau and Central Military Commission also set up hundreds of appointments to meet with members from the 18th Central Committee and leaders from a number of military divisions to hear their ideas. On September 25, a preliminary candidate name list was drafted and submitted to the Standing Committee of the Political Bureau. The final list was approved on September 29 before it was turned over to the 19th National Congress for a vote.
Sources: Xinhua, October 24 and 27, 2017
http://news.xinhuanet.com/politics/2017-10/24/c_1121850995.htm
http://news.xinhuanet.com/politics/19cpcnc/2017-10/26/c_1121860147.htm