Search google video for 'John Petrucci Rock Discipline'. Somehow this excellent instruction video has been made available for free there. It will certainly sort you out if you follow his practice advice, but it does get pretty advanced. I found some of his warm up exercises to be well nigh impossible, let alone the proper scales and things themselves!
Good luck!
The Pulp Fiction theme isn't that hard, to be honest, it's pretty much all played on the low E string. If you try hammering-on and pulling-off a lot, it can sound just as good as picking the notes.