here's what i did with louis (6 months and weights 6.8lbs).
i used collars at the beginning but he hated them. HE WOULDNT WALK, PERIOD. i got very frustrated and looked online..i found out that if u get a harness (which is easier for small dogs) and let him play with it first, put it on him for a few mins prior to going out, they'll start to like them. so i did this and now louis loves his harness, as soon as i grab it HE KNOWSS HES GOING OUTSIDE
so he starts jumping up and down. collars in my opinion just tend to choke the poor puppy, i rather use the harness.