pp have given some excellent pointers. dog obedience is a must but my biggest thing with a jack russell would be being dominant. reward based training is all very well but with some dogs (like jack russells) are known to suffer from selective hearing/obedience, if you are "pack leader" they will listen. if hes not responding to no try a sharp "sshht" or a tap or the ribs with your finger tip. AND i cant recommend walking him enough, he is a high energy breed and will need a good walk (30min+) every day, better if its before a meal so the dinner is a reward. ideally one in the morning one at night, it takes 20min for the average dog to get into a good relaxed frame of mind and enjoy the walk. you want to keep walking for a bit after they hit that frame of mind. if hes not exercised enough you will find him misbehaving more and will be less willing to listen during training.

if you want more ideas i cannot recommend cesaer milan's books enough (or just watch the dog whisperer if you have foxtel/austar) they have been the only techniques that have worked on my crazy bouncing (no no really actually bouncing) cavalier x mini poodle, she even failed basic obedience training!

ETA: do as i say not as i do!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!