How one can keep his/her audience involve throughout training sessions?

Latest technology:people get attracted by latest methodology and equipments,so this is now essential part of training session Material:one's material should contain brief and precise point of view..to many slides always make your audience lose interest.
provide hands-outs in the middle of session containing few but small test (like MCQs or best choose answers, this activity will involve them during entire session).
your session must contain open ended question or alternate point of views from audience side.
Rewards:small rewards will help them to be in session.