haha.....oh, I remember the frustration, and it is actually still happening every so often as Millie is just 6 months. The best advice I got was to consider it as becoming a habit. As annoying as it can be to take them out constantly, they will eventually learn that that is where to go, just as we know to use the toilet. It's not like we even think about using teh toilet, or consider anywhere else, it has just become habit. If they make a mistake, just clean it up and go on about your business, and then try to take your pup out more often and give praise when they go in the right place.
It is all about time. Millie has started to stand by the door, even though we still try to take her out when it is convenient for us, as we don't want to be ruled by HER schedule!
Yes, make the crate as small as possible. Seems cruel, but we only had one accident.