I'm terrible with rejecting people...need advice!

While chatting on FB the other day, a friend asked me out for dinner and drinks. I knew straight away that it was intended to be a date, but I didn't know how to say no...I was kind of put on the spot. I have no intentions of dating him. I figured I'd have dinner with him this time, but then think of a way to distance myself later. But then other people are saying that it'll be harder to back out later after already going on a date, and I should just not go to dinner at all.



So what do I do? Find an excuse and cancel, then keep saying I'm busy when he tries to reschedule? Or still go to dinner but don't act too friendly? Or tell him I'm not sure if it's a date, but I only just see you as a friend?