As a corporate trainer and an adjunct professor, one of the things I stress is applying what you learn.
I tell my participants/students that if they “throw their notes up on a shelf and never look at them,” then it has been a waste of time – both theirs and mine.
I then suggest that the best way to reinforce what they learned is to teach others.
This can be part of a team meeting or as a component of a project or even talking to a friend.
One of my clients requires their employees who attend to a conference to schedule a meeting with others in the company and teach them what they have learned otherwise they will not pay for the conference.
To do any of this effectively, one must be present during the training by listening intently and asking questions when there needs to be clarification.
It always amazes me when the participants just sit there and not take notes. 
I purposely don’t have a lot of text on my slides; the reason is because the participants are too focused on reading and not listening to what I am saying.
I use many visuals to emphasize important points, just as the saying goes “a picture is worth a thousand words.”
Another thing that I find challenging is after a presentation (or several if at a conference), participants tend be motivated to act… until they get to their car.
As they get further away from the venue, their excitement starts to wane. For this reason, I give them “homework” at end of the training by having them identify one thing they can do within the next 48 hours that they learned.
Then I make them write it down as a reminder.
This way they hopefully will be encouraged to take the time to review their notes, talk to others, and then make an earnest attempt to use their new skills.
With the cost of college so high as well as prestigious conferences, it really behooves participants to get their monies worth.
However, time is even more valuable than money and you can’t get time back so be selective on what trainings/presentations you attend, pay full attention to the presenter, and determine the best way to reinforce what you learn.
Knowledge is power so the more you learn the more effective you can be in both your personal and professional lives.