There isn't really a quick fix for pulling (though the halti may help).  You really need loads of time and patience, stopping every time they pull and only walking on when they relax by you - it can take a long time to get to the park! I sometimes walk my friend's dog, who does pull a lot as my friend has not trained him properly and it is exhausting, isn't it? Do you have a big enough garden to play ball, as suggested?  That could take the edge of his energy.  Sorry I am not much help, good luck,

Carolyn x