Find the critics.
I recently met an engaging, accomplished professional who described one of his keynote speaking engagements to me in glowing terms. Coincidentally, I knew several audience members who had a less-glowing impression of that speech.
Since I sensed that he could take it, I let him know that the rave reviews weren’t universal. To which he responded, “But (person who hired him) sent me a great testimonial! And people lined up to shake my hand afterwards!”
I pointed out that anyone who hires you wants to declare your speech a success – why would they want to be associated with a failure? And of course people will want to shake hands and chat with someone successful and charismatic.
My point was to encourage him to look past the easy, often self-interested praise that comes our way. If our goal is to improve, we need to find people who are willing and able to give us the honest, sometimes tough feedback we need to keep getting better.
P.S. This new friend accepted my offer to review his speech free of charge and provide feedback. A few days after I sent the feedback, he hired me to help him improve it!