There are two things you should teach every dog and everything else is easy 
One is reflex to their name and the other one will help with everything you do especially loose lead walking - it is simple, it is the magic pill, it is fool proof, I may have to kill you if you know this simple cure all method as I will be out of work 
Don't stand still, don't turn around the dog just get really frustrated and you never get to go on a walk as you are standing still or going back the way you came!
Get some yummy treats, dog on a lead, you can be sitting down if you like to start with. Every time the dog looks at you in the eye give him a treat - it is that simple. No words, no luring just reward eye contact. Do not have a treat in your hand as the dog will look at your hand.Just dog looks at you you get the reward from your treat bag or pocket and reward.
Start with this at home,then go and sit in the park and do it there, go everywhere and just reward the eye contact - do not worry about loose lead for a day or two (after all they have been pulling for months what is one more day!)
Next stage when eye contact is pretty often stand up and wait for eye contact, reward, take a step and wait for eye contact and reward,take a step backwards, sideways walk like a drunk person but reward all eye contact.
No pulling no stopping no getting frustrated just relaxed rewarding eye contact.
No dog and I mean no dog can pull forward and look at you to give you eye contact.
All you do need to do is to proof the eye contact when their are distractions and this can take a bit of planning eg if I take my collies to a tennis match that would be hard for them but if I gave enough distance I would get the eye contact and could then move nearer etc.
Default behaviour for all dogs is to check in with you at regular intervals for a reward easy peasy and it is foolproof.
I love teaching this method it always works and it is so easy to do -let me pop over and introduce it to your dog 