It may seem difficult to evaluate the progress of your presentation while you’re giving it, but skilled speakers monitor the room.
Look for audience cues such as interest or boredom. Note the questions people ask as they may point to areas that need clarification. If it’s appropriate, you can even stop and ask the audience for their input on how it’s going. This may allow you to change tacks if necessary. When possible, have a random spectator take notes on audience reaction. Once it’s over, do a thorough post-mortem. Was your objective achieved? Did the audience seem engaged? Note what went well and what didn’t. Ask for feedback from credible participants. If you’re making the presentation again, how will you improve it next time?
Adapted from the Harvard ManageMentor Online Module: Presentation Skills.