When communicating in a group setting, how do I keep the group engaged with what I am saying?

By make it interactive , you can ask questions to involve them in the conversation.
It's also important to avoid the monotone rythme while talking; always try to change the tone of voice.

1.
Know target audience.
Are there words or phrases that the audience can relate to.
Are they interested in the topic?2.
Aim not to use too much jargon.
Sometimes listeners can feel left out if they do not understand certain specialised words or phrases.3.
Vary tone of speech, use imagery and creative words to get messages across clearly.4.
Keep focussed - what is key about the message.
Repeat key words which are essential for planting in listeners minds what you are trying get across and what they can remember and take away with them.5.
When speaking pick out members of audience to keep eye contact with.
This gives listeners message that you are interested in what you are saying and welcome feedback from them.6.
As you deliver each section of your speech, ask audience if they understand what you are trying to convey to them.
.7.
Listen to their answers and give them your undivided attention.
Summarize their main points so that you understand what they are asking and they are sure you understand their points.
Stop talking and welcome questions.
Whenever you feel like the audience is not engaged, try asking questions and listening first to see what happens.
This can be useful for both the audience to find out more and for you to see if there are any areas which need more research or work.
Be respectful of questions asked even if they are obvious or you have to repeat an answer.8.
Even listen for silences.
Does the silence mean that you have totally lost the audience or that they are still digesting the information given to them.
Explain things in simple way, the simpler the better.

Know your audience before you speak.
Draft your speech in such a way that it first interest you, when you keep yourself as a part of the audience and think.
Make your speech a little more interactive, involving the audience by asking them brief questions.
Maintain necessary pauses when needed in your speech.
Add a little Humor to your speech, even if it is a board meeting, we should remember that the people who are attending are all humans and not robots.
Everyone would like to have a laugh or a break in the midst of serious discussion.
But be careful on what kind of humor you add, it should be relevant to the topic you are speaking on.
Add voice modulation in speech, don't go on a flat tone from the beginning till the conclusion of your speech.
Maintain eye contact to maintain confidence in yourself and your listeners.

When your speech is totally a speech only without your audience interaction then you must do something.
Let your speech be more interactive.
Ask questions? yes but its pretty used all the time.
Try something like, make a puzzle with answer on their hands while you have the questions.
Bingo style puzzle and the more correct answer they get a small prize, So audience will try their best to win too!

You must make the communication engrossing with the right words and fill in as many examples as possible.
Also, make a few moments lighter.
To top it all, the conversation has to be two way or three way, in accordance with the number of the persons in a meeting or a conference hall.

Hi _ First pay attention to the speech or content, think about your communication skills, body language, eye contact, listen what group people are asking, have complete command on the topic of the discussion, ask questions.....