The trainers I used walked their dogs at a distance gradually getting closer while we walked in another field with fences between us.
Shaddo became excited as soon as she saw the other dog and we never got close enough to meet up.
We have been training like this for months and we don't seem to be improving at all.
She has never to my knowledge been off the lead and allowed to play with other dogs. I have been advised that I should avoid meeting other dogs. She slipped the leash twice in the past and bounded up to the other dog which resulted in the other dog becoming defensive and she turned away. Opinion is that she is not aggresive but desperate to play and socialise.
I train her at home every day to walk to heel,sit, leave, stay and we play hide and seek with her toys and treats. No distractions at home and she is fine.