Bonnie, I was taught to use a metronome for speed (piano). Just like you said, move it up one notch at a time, it's kinda like the straw that broke the camel's back! I could always work up to a faster speed this way. Also, about the syncopation...I also found it helpful in working for speed to practice accenting different beats. I'm not sure if this reinforced the muscle memory or just kept me from getting bored.