Salsa tips to teacher
The teacher should rotate the partners once every two tries. That way no one has to wait a long time before trying, if the group does not have a 1:1 male/female ratio.
Who to rotate
Rotate the gender that there are more of. Rotate them counter clockwise. If you rotate the students according to the same rules every day you have a lesson, the students will eventually remember the rules which will result in less confusion about how to rotate.
Remind to watch once, try once
When the teacher shows a new move, he should remind the students to only watch the first time. Many students try to mimic the teacher as he demonstrates. That makes it impossible to see parts of the move. Students are often eager to try the new move sooner than possible. They have a lot to think about and often forget to watch the first time and try the second time. Remind the students about this before every demonstration.
Use hand signals
The teacher should make a signal just before he shouts the name of the next move everyone are going to make. Then the students who can't hear the teacher can at least see the signal. The signals should be able to be done using the teachers hands above his head to maximize visibility for students farther away.
Demo each move several times with different focuses
Many teachers demonstrate a new move only once before the students are supposed to try it for themselves. There are many components in a move. The students should focus on watching only the feet and legs in the first demonstration. Then the teacher should do the exact same demo but say to the students to now focus on the arms and ignore the legs. Many students' eyes jump randomly between observing how the legs move and how the arms move. They don't catch the whole move that way.
Perhaps the group could practice just putting the feet in the correct place at the correct time, a few times, before even watching how the arms should have moved at the same time.
Give a link to complete sequence after course end
The teacher should give a link to the sequence everyone has learned so far, so the students can print it out or read directly from their computers if they have forgotten a component of the sequence they just learned. It is easy to cut-n-paste parts of the Salsa (legal move combinations) page into a new page describing the sequence in question. Example.