I remember when I first started making public speaking presentations.
 I was scared, nervous, and was always seeking the approval of the audience.
I wanted to be able to a person that would capture their attention, to make them feel engaged, and ensure that they would listen.
At first I would do what many speakers when first starting off would do, I would ask the audience a series of questions or just one question to get the audience mentally involved, but this didn't have much success at times.
There would be people putting up their hand to answer the question, or it was the type of question that was "How many people here have...
" I soon realized that this technique was not effective, because it would only target certain people.
What started working was for me to ask a series of questions that would get every person's attention.
Let me illustrate this with an example.
Let's say I'm standing up in a room and I'm taking to people at a seminar I'm holding.
"How many people are here to learn the secret to being a great conversationalist, please put your hands up?" Then there's a few people in the room who do put their hand up.
However this simple question may not address the people who are not there to be a great conversationalist.
There's a chance that the people came because their friend dragged them to come along or maybe they are there because they were bored.
What needs to be done is to continue to ask another question that would require audience participation.
I might ask "How many people are here because a friend recommended them to come, please raise your hand?" In this case, the question would then address another sub group within the audience.
However there's still a group, and this always inevitably happens, that there are people that just refuse to put their hand up.
This is when I ask a third and final question, "How many people just decided not to put their hand up, please put your hand up?" Even though this doesn't guarantee that everybody will put their hand up, it does mean that you've gotten the attention of everyone in the room.
The questions asked ended up into two major groups, those that raised their hands and those that didn't.
And by asking questions that get the majority to raise their hand to your question, you can always end up asking the simple question of "How many people decided not to raise their hands, please put your hand up?" This is a fun and easy way to get the attention of everyone in the room.
If you also happen to be speaking in front of an audience and you are looking to create a little bit more humour.
Then one thing that I always suggest is to go "Okay, how many people didn't put up their hands because they were busy texting someone at the time?" This will get people laughing because it's true.
I've taught and watched at other seminars the number of people texting and not participating.
If you want to add that extra fun, try using the line above.
If you are trying to ask questions to get people, ensure that you ask questions that is going to address every single person in the room.
Don't just aim at a specific group, or else you'll lose the others that aren't part of the group from the very start when you begin speaking.