[Raven]

its never to early...i had one leash trained at 10 weeks old and after that i needed no leash. ...................
this is what you do: you take a ten foot rope and have it coiled
in your right hand always keeping the dog on the left at all times her shoulder to your leg in tight and close. you walk down the side walk or trail and everytime the dog sniffs the ground or decides to take her eyes off of you to investigate a different direction you drop the slack from your right hand and do a quick right turn ... without looking back and march in a straight line.
the dog will (yes it sounds mean) suddenly get yanked back to the direction your walking and strive to catch up. Its best to be silent so she looks only for visual clues. Eventually and it wont take long...the dog figures out ...gee everytime i take my eyes off that S>O>B he turns and i get YANKED. Soon she won't dare take her eyes off you (again "EYE CONTACT") and will stay
at your side without thinking to wander or drag you.
Also remember that if your walking on a sidewalk and about to CROSS a street always stop before doing so and have the dog sit.
look both ways.....then proceed when there's NO Traffic!