I like the idea of praise in the classroom. Public praise of a student's work is great to build camaraderie and teamwork. Even private praise can be useful for fostering a desire to stay on task. Empty praise (praise for the sake of giving praise) is quickly spotted by the adult learner, and needs to be avoided in lieu of genuine praise. One teacher I admire would ask opinion questions of individual shy students. These "no wrong answer" questions can then give the opportunity for the faculty member to thank the student for sharing, and then can lead the way to more complex Q&A.