Don't worry too much about trying to stay exactly on the line. That makes you go too slowly and 'jiggly'. Instead strive for smooth movements, even if they're off the line a bit - after all, no one will ever know as that line is not marked on the quilt!
And the suggestion to try it a few times without turning the machine on is a good one. The more you do it, the more your muscles remember the movements and the more automatic it becomes.