The only way they'll consider investing time with you is if they see some value in doing so. Do Have an Interest-Creating Opening. Depending on what you're doing now, and your objectives, this might be something worth taking a look at. I'd like to ask a few questions to see if you'd like more information. Do Ask Questions.
Some pundits suggest going for the appointment quickly, and never divulging information.
And, if the prospect is qualified and has interest, I can pique their curiosity a bit by phone, and presell them on what we'll speak about when I arrive. Then narrow down a convenient time for both of you. Do Make a Confirmation Call. Some might suggest this gives them a chance to cancel. And if they're of this mindset, they either wouldn't be there when you arrive or they wouldn't give you the time of day.