Of course you have to know what to improve. If you don't know, ask around - not for vague reassurances, but for specific points that could be better.
Speaking too softly? Speaking too fast? Not enough enthusiasm? Not enough animation? Not enough eye contact?
Let's suppose, for example, that you're told to speak up. Make your voice stronger. More projection.
Got a meeting coming up?
Arrange for silent, real-time feedback from a conspirator in your audience
Go to a trusted colleague. Ask for instant, subtle signals from the back of the room. Agree on the signals. Voice still too soft? ...Palms will move upwards. Too strong? ...Palms move down. Just right? ...Circle thumb and forefinger.
It's a terrific way to overcome the fearful inner voice that usually stops you trying to improve, whispering that you'll look stupid or 'over the top'. (I call that fearful inner voice your GRIM REAPER - if you let it have its way it would keep you in bed all day hiding under the blankets.)
Why real-time feedback from a trusted colleague is so effective
Conspirator feedback has everything going for it. When you get that circled thumb and forefinger, the fear stops and you keep speaking knowing instantly that the new way is working. That consolidates. That lays new tracks in the brain. Real, lasting and confident change.
You might have to get that specific feedback a few times in different meetings, because your grim reaper is likely to resist.
Just one thing you might have to check with your colleague conspirator before you try it out. Your colleague already knows you and has a feeling for who you are. You're about to disturb that. He or she could be too strongly affected by the thought, This isn't the you that I know, when the thought should be Does this change work for you?
Which raises that eternal question, Who am I?
More on that another time.