I have done a fair amount of public speaking, but mostly academic and disability rights. Nothing that would go down to well for a corporate lunch.
However some things are common to all kinds of speaking. First and foremost, do some audience research and get a feel for who you are talking to, What goes down well with one audience may well bomb with another.
Visual aids/slides help but be prepared for the technology to go wrong, in fact be prepared for just about anything to go wrong.
I have always found that humour works, but then you do have to be careful that your brand of humour is not offensive to some audiences, again that is where audience research comes in.
Above all, get used to being out in front of an audience, you will likely always be nervous, but the more often you have done it, the more confident you will become once you get going.
I myself am not impressed by many "inspirational" speakers, there is term in the disability world "inspiration porn" which essentially turns some people off. Again though that depends on the audience, if you have done truly interesting things there are bound to be people who would like to here that, not so much to be overtly inspired, but because they are interested, so don't overdo the inspiration and make it relevant to the audience so that they feel it is not beyond them.
And lastly always give your best performance regardless of whether it is an audience of 5 or 500, when you are speaking to a large audience, act as if you are just adressing a few of them gathered around a table.