Classrooms is easy to conduct but hard to prepare, this is my initial assessment, especially when I was a new trainer.
Supervisors: they have to know why I am taking people out for training that means they have to operate without that one personnel which sometimes effects production time. But knowing I m pulling their staffs out earlier means they can also plan for anything to happen.
Learners: They need to know why they are coming for training, what are the expectations of the training programs, what will they learn, how will they be learning, where will it be, etc. It is also good that an email is sent to them to prepare for the training. When writing to them, I usually write as if something fun is going to happen in the training classroom. (also better make sure the program will be fun for them otherwise the next time you send an email, they might not believe you) This breaks the ice with them.
Training materials- sometimes I see the training materials that is set out for me before I start the training program, I groan in despair and go "This is going to be a long boring day". Sometimes it is good to make the materials is more fun, more pictorial instead of having a large technical reading manual which is good for collecting dust back in the office. Try using comics format for illustration of processes, graphics helps a lot.
Activities- I try to not talk more than 15 minutes at the beginning of a topic. I just introduce but then I turn the session into an activity. People must get out of their seats and do something to learn. Learning should not be passive, it should be active. It creates an environment to learn. Example: I had to teach a topic which was something really new in the industry. So instead of showing people how to use the service- I got the devices ready with simple comic-like illustration and I had a competition amongst the groups. Everyone had to prove that they can use the device and show it to someone else in the group, when "evidence" has been proven they sign on their training book and I give a time limit. What happened was people start learning from one another, someone who was more technically inclined helped those who were not. I went to some who needed help but mostly they learnt it on their own.
Music- learn about music and how it helps in training. I don't know whether there are studies about this but because I m not into a certain one types of music and I like many types, I tend to use music to help in training. It's like watching a movie- when I was young it was not the shark in Jaws that really frightened me the most- although the sight of the beast scared me, it was John Williams soundtrack of the attack that scared me more. So I try to find out the learners that attend the sessions, of their age or race and see what music I can use to start the session. When activities, I use a more exciting song and so on and so forth.
Jokes and one liners- I try to use a lot of humor to lighten up the classroom. It also creates a lively environment, people are excited to try new things. I always tell the class "Better to make the mistake here than back in the workplace, the most is you might get your friends here laughing at you, back there you can get into trouble" You can check out one-liners from http://www.siglets.com.