In most cases, when this sort of thing comes up I say something like: "I have some dietary restrictions and wouldn't be able to eat there; could we meet at $other_restaurant instead?".
For someone known to be observant, I would instead say something like: "last I heard they aren't kosher; has that changed?" That is, presume that the other person has the same problem you do. So either he'll say "no, they're under supervision now" (great!) or he'll explain how he's planning to solve the problem ("yeah, I know, but they have a fruit salad that works").
What to do if the person is a non-observant Jew is more complicated. Unless it's someone you're close to, anything that sounds like rebuke over his non-observance is likely to cause resentment. I've found that modeling better behavior without pushing works better, so I personally would use approximately the same approach as for gentiles, making it about my needs and leaving unsaid that perhaps he ought to be considering that too.
Finally, I've been assuming in this answer that this is a meeting between the two of you. If, instead, it's a larger group for business purposes (your sales team is taking the customer out to a swanky steak house, for example), you might be better off going and drinking a Coke than trying to influence the decision. You have to judge such situations on a case-by-case basis. (For additional thoughts on workplace meals, see this question (h/t msh210).)