Hi, I would also recommend the long lead. I have to admit to being very reluctant at first, but we stuck it out and I'm so glad we did. After about 6 weeks, I used to let go of the lead and he trailed it behind him and then gradually we managed to do without it altogether.
When you're walking, praise and reward everytime he looks up at you - even if he's up ahead and turns to see where you are, praise him, the idea is to get him to learn that he needs to keep you in his sights all the time,If he goes off ahead and disregards you, try turning round and going the other way, you can also try hiding. BIG rewards for an immediate recall and try to vary the rewards, it doesn't always have to be food, a game will also keep him motivated and focussed on you.
They can be real little teenagers at this age but if you're if you're consistant with training now, it'll pay out later on. Best of luck, keep us posted!