No expert here but we started in the house and garden - feeding his meals as he walked beside us no lead.
Then added lead in, did the same in house and garden.
Then moved to driveway/front path - this took much longer as lots going on.
Then moved to outside the house. I started almost constantly treating every step, then moved to two steps and got to about 35 steps before PoirotPup will then run and sit in front of me like he’s saying ‘where’s my treat’.
For us still a work in progress and I was told it would be for some time. I try to use one lead for when i’m training it and use the other long line for when he can sniff more.
I haven’t done it yet but have read that if he is pulling to basically turn and walk the other direction and treat as soon as he is back in position. I did have to use higher value treats as we moved outside and to the pavement. I try to do it on a short section down to an area where I then switch to longline and give him big praise/treat and then lots of sniffing/long lead time!
I definitely wouldn’t say we’re there yet and someone else might have better way than me but it seems to be working. I say ‘walking, walking, walking’ because I forgot to pair it with ‘heel’ and accidentally said that initially but now if I say it he will trot for a bit waiting for his treat 🤣