
One way to get a good recall is to make sure that your dog enjoys coming back to you, I teach what I call a "happy"recall
I also start training in the garden asap. You will probably what to start on lead as your puppy is 8 months old(I don't have a problem with that although I train off lead all the time ;) )
Starting with him is a sit or down whichever you want & take a step directly in front of him & taking couple of steps backwards & calling him on the second step & maing a big big fuss & treat if you want
Gradually increase the distance when he is steady on the previous distance until you are at the end of your lead length(the longer lead the longer the distance ;)), all the time making sure you make a big big fuss when he gets to you
When he is steady on lead go back to stage one off lead & when he comes to you clip on the lead & then treat/fuss This means that he will see putting the lead on as the precursor a treat
This method means your dog comes back because he wants to be with you & knows he will be rewarded
When you first let him off it is best to try to be in a fairly distraction free area & don't forget the treats & praise & lead on & then release, if he loses concentration on you you can try kneeing down facing away from him & talking to the ground or imaginary dog/friend etc in a silly funny voice & when he does come back make a fuss after clipping on the lead & treat
I would also as a separate exercise an instant stop/down. Can be done on lead again to start, simply doing some heelwork without stopping put him into a down & walk round him, at first staying just around him but later walking further & further away when he is going down on command without being touched you can do the exercise off lead & when he has grasped this you are halfway to the distance down. Next step is to be playing with him & give him the down command & go to him(telling him down all the time) & praise & treat whilst he is in the down & clip on the lead & treat again when he has grasped this you can start to combine it with the recall to make him think what is coming next & engage his brain
Best of luck