Riley is just over 4 1/2 months so we are right there with you. When we started puppy class we had a wonderful trainer who told us to make it a party. What she had me do was at first lure her to walk beside me with a treat (I use Wellness treats cut very small, they are soft and she can chew them quickly). As she walks praise her like you're having a party. "Good walking, good girl!!" Treat her frequently. This worked great for us. Now when we walk I start of by saying, "Let's walk!" She begins, treat. If she walks without pulling it's, "Good girl!", treat. When she begins to pull I say, "Let's walk nicely!" When she loosens up the leash so there is slack, "Good girl, good walking!", treat. We carry on like this for the whole walk, twice a day. I'm sure my neighbors think I'm crazy but it really works. We went through 2 five week sessions of puppy class. Then last week we began basic obedience. Riley was the youngest in the class and the most well behaved. Several people commented on it. All that partying is paying off.