[1] The section principal demonstrates leadership not only through a high standard of playing, but also through verbal communication and body language.
The role of section principal requires one to play at a high level, and to be a team leader with competent people skills.
During rehearsals, principals often are expected to contribute musically and technically to the music-making process by making appropriate suggestions to the tutti players.
Section players look to the principal to obtain entrance cues, and orient their playing to their leader's style, dynamics, articulation, and phrasing, among other things.
[1] In addition to leading the section, principal players are responsible for playing any solos written for that voice in a given musical score.