How do I teach my dog to COME no matter WHAT is going on?

All the recall training I've attempted didn't really work. One thing was to put him on a really long lead, throw a ball and then call him--if he doesn't come then reel him in. He's a Border Collie (smart) and I did that once and he wouldn't go past his length of rope to get the ball, but wouldn't come, either. How can I teach him to come whenever I ask?