"I've been singing for years. I think people would tell me if I sucked." (By the way, he sucked.)
A lot of speakers truly don't know how they're doing, especially those with lots of experience who've been doing it for a long time. They are comfortable in their routines, comfortable with the applause and the polite smiles, and comfortable in the knowledge that they're being asked to speak, even if they're not getting repeat engagements with the same organizations. They probably don't suck, but they may be in denial about their effectiveness.
But how do you know? Will your family tell you? No way. Will your friends tell you? Maybe, but probably not. Will your employees tell you? Are you kidding?
Where can you get honest feedback that's not influenced by your relationship with the giver?
1. Anonymous evaluations
If you've never had your audience fill out evaluations, they're worth giving out now and then. A few simple questions will tell you a lot about your presentation: What worked, what didn't work, what would they like to learn more about?
Then, don't be too obsessed with the outcome. It's easy to dwell on the one or two low scores or negative comments out of 100, so don't take it too personally, but look at the evaluation as an opportunity to tailor your presentation even more to what the audience is looking for. Here's a compilation of responses from speakers about how they deal with a negative evaluation. And here are a couple of my previous posts about evaluations.
2. Videotape yourself
This works if you can be honest with yourself. My clients tend to discover that they're doing much better than they thought they were when they see themselves on video. At the same time, bad habits are very clear: distracting gestures, repetitive crutch phrases, movement without purpose. It's all plain to see when you watch video of yourself. Maybe if season 7 American Idol contestant Kyle Reinneck had videotaped himself before his audition, he wouldn't have been so surprised at the judges' response (Kyle is not the person I quoted at the top of this post. Kyle could be better, but he doesn't suck).
3. Hire a coach
Elite athletes at the top of their game still rely on coaches to help them refine their skills and get the most out of their natural abilities. A speaking coach can do the same for you, and will be the most neutral party you can find to give you feedback on your content and delivery. Here's a great post on why someone hires a coach. Favorite line: "You hire a coach because you recognize that the best investment can make in your future is in you." I've heard of speaking coaches who are downright mean, but a good coach will never humiliate you or try to discourage you.
Don't live in denial -- use these tools to find out if you suck. You probably don't, but wouldn't it be nice to know for sure?