i had a collie i taught to walk without a lead,sit n stay etc,i did it with biscuits.
rewarded him when he got it right and kept biscuit back till he got it right,and just weaned the amount of biscuits down till he didnt need any and it was 2nd nature,never put him on a lead since he was a yr old,would wait out side shopping centers and shops,could go in to local shopping centre and b half hour,he would stiil be there when you got back,awesome dog.